diff --git a/client/src/api/client.behavior.test.ts b/client/src/api/client.behavior.test.ts
index 71837160a..e33de84f8 100644
--- a/client/src/api/client.behavior.test.ts
+++ b/client/src/api/client.behavior.test.ts
@@ -111,7 +111,7 @@ describe('client > request interceptor', () => {
     expect(sink[0].headers['X-Idempotency-Key']).toBe('queued-key')
   })
 
-  it('FE-APIWIRE-004: falls back to a random token when crypto.randomUUID is missing', async () => {
+  it('FE-APIWIRE-004: falls back to getRandomValues when crypto.randomUUID is missing', async () => {
     const realCrypto = globalThis.crypto
     vi.stubGlobal('crypto', {
       getRandomValues: realCrypto.getRandomValues.bind(realCrypto),
@@ -120,9 +120,30 @@ describe('client > request interceptor', () => {
     const sink: InternalAxiosRequestConfig[] = []
     await apiClient.post('/probe', {}, { adapter: okAdapter(sink) })
 
-    const key = String(sink[0].headers['X-Idempotency-Key'])
-    expect(key).toMatch(/^[a-z0-9]+$/)
-    expect(key).not.toMatch(/-/)
+    // randomUUID needs a secure context, so on the plain-http installs the
+    // README documents this branch is what actually runs. getRandomValues has no
+    // such requirement, so the fallback is still a full v4 UUID.
+    expect(String(sink[0].headers['X-Idempotency-Key'])).toMatch(
+      /^[0-9a-f]{8}-[0-9a-f]{4}-4[0-9a-f]{3}-[89ab][0-9a-f]{3}-[0-9a-f]{12}$/,
+    )
+  })
+
+  it('FE-APIWIRE-004b: the last-resort key is never degenerate, even with no Web Crypto at all', async () => {
+    vi.stubGlobal('crypto', undefined)
+
+    const keys = new Set<string>()
+    for (let i = 0; i < 50; i++) {
+      const sink: InternalAxiosRequestConfig[] = []
+      await apiClient.post('/probe', {}, { adapter: okAdapter(sink) })
+      keys.add(String(sink[0].headers['X-Idempotency-Key']))
+    }
+
+    // The old fallback was Math.random().toString(36).slice(2), which is not
+    // length-stable: 0.5 yields a single character and 0 yields the empty string.
+    // An empty key makes the server skip deduplication entirely, so a retried
+    // write applies twice.
+    for (const k of keys) expect(k.length).toBeGreaterThan(16)
+    expect(keys.size).toBe(50)
   })
 
   it('FE-APIWIRE-005: the socket id header is omitted while no socket is connected', async () => {
diff --git a/client/src/api/client.ts b/client/src/api/client.ts
index d3c60819c..4b3887977 100644
--- a/client/src/api/client.ts
+++ b/client/src/api/client.ts
@@ -1,6 +1,7 @@
 import axios, { AxiosInstance } from 'axios'
 import type { z } from 'zod'
 import type { Place } from '../types'
+import { randomId } from '../utils/randomId'
 import {
   weatherResultSchema, type WeatherResult,
   inAppListResultSchema, type InAppListResult,
@@ -151,10 +152,7 @@ apiClient.interceptors.request.use(
       // The mutation queue sets its own pre-generated key; skip if already set.
       const method = (config.method ?? '').toLowerCase()
       if (MUTATING_METHODS.has(method) && !config.headers['X-Idempotency-Key']) {
-        const key = typeof crypto !== 'undefined' && crypto.randomUUID
-            ? crypto.randomUUID()
-            : Math.random().toString(36).slice(2)
-        config.headers['X-Idempotency-Key'] = key
+        config.headers['X-Idempotency-Key'] = randomId()
       }
       return config
     },
diff --git a/client/src/components/Admin/AddonManager.tsx b/client/src/components/Admin/AddonManager.tsx
index c30e92fb9..7ae90b72e 100644
--- a/client/src/components/Admin/AddonManager.tsx
+++ b/client/src/components/Admin/AddonManager.tsx
@@ -196,7 +196,7 @@ export default function AddonManager({ bagTrackingEnabled, onToggleBagTracking,
                           <span className={`hidden sm:inline text-xs font-medium ${bagTrackingEnabled ? 'text-content' : 'text-content-faint'}`}>
                             {bagTrackingEnabled ? t('admin.addons.enabled') : t('admin.addons.disabled')}
                           </span>
-                          <button onClick={onToggleBagTracking}
+                          <button type="button" onClick={onToggleBagTracking}
                             className="relative inline-flex h-6 w-11 items-center rounded-full transition-colors"
                             style={{ background: bagTrackingEnabled ? 'var(--text-primary)' : 'var(--border-primary)' }}>
                             <span className="absolute left-0.5 h-5 w-5 rounded-full bg-white transition-transform duration-200"
@@ -222,7 +222,7 @@ export default function AddonManager({ bagTrackingEnabled, onToggleBagTracking,
                                   <span className={`hidden sm:inline text-xs font-medium ${enabled ? 'text-content' : 'text-content-faint'}`}>
                                     {enabled ? t('admin.addons.enabled') : t('admin.addons.disabled')}
                                   </span>
-                                  <button onClick={() => onToggleCollabFeature(feat.key)}
+                                  <button type="button" onClick={() => onToggleCollabFeature(feat.key)}
                                     className="relative inline-flex h-6 w-11 items-center rounded-full transition-colors"
                                     style={{ background: enabled ? 'var(--text-primary)' : 'var(--border-primary)' }}>
                                     <span className="absolute left-0.5 h-5 w-5 rounded-full bg-white transition-transform duration-200"
@@ -269,7 +269,7 @@ export default function AddonManager({ bagTrackingEnabled, onToggleBagTracking,
                                 <span className={`hidden sm:inline text-xs font-medium ${provider.enabled ? 'text-content' : 'text-content-faint'}`}>
                                   {provider.enabled ? t('admin.addons.enabled') : t('admin.addons.disabled')}
                                 </span>
-                                <button
+                                <button type="button"
                                   onClick={provider.toggle}
                                   className="relative inline-flex h-6 w-11 items-center rounded-full transition-colors"
                                   style={{ background: provider.enabled ? 'var(--text-primary)' : 'var(--border-primary)' }}
@@ -459,7 +459,7 @@ function LlmParsingConfig({ addon }: { addon: Addon }) {
             <div className="space-y-3 rounded-lg border border-edge-secondary bg-surface p-3">
               <div className="flex items-center justify-between">
                 <span className="text-xs font-medium text-content-secondary">Installed on the server</span>
-                <button onClick={loadModels} disabled={loadingModels} className="text-xs text-content-muted underline disabled:opacity-60">
+                <button type="button" onClick={loadModels} disabled={loadingModels} className="text-xs text-content-muted underline disabled:opacity-60">
                   {loadingModels ? 'Loading…' : 'Refresh'}
                 </button>
               </div>
@@ -470,7 +470,7 @@ function LlmParsingConfig({ addon }: { addon: Addon }) {
               {installed.length > 0 && (
                 <div className="flex flex-wrap gap-1.5">
                   {installed.map(name => (
-                    <button
+                    <button type="button"
                       key={name}
                       title={name}
                       onClick={() => setModel(name)}
@@ -509,11 +509,11 @@ function LlmParsingConfig({ addon }: { addon: Addon }) {
                           )}
                         </div>
                         {installedHere ? (
-                          <button onClick={() => setModel(m.id)} disabled={active} className={`shrink-0 rounded-md px-3 py-1.5 text-xs font-medium transition-colors ${active ? 'bg-surface-tertiary text-content-muted' : 'border border-edge-secondary text-content-secondary hover:border-edge'}`}>
+                          <button type="button" onClick={() => setModel(m.id)} disabled={active} className={`shrink-0 rounded-md px-3 py-1.5 text-xs font-medium transition-colors ${active ? 'bg-surface-tertiary text-content-muted' : 'border border-edge-secondary text-content-secondary hover:border-edge'}`}>
                             {active ? 'Selected' : 'Use'}
                           </button>
                         ) : (
-                          <button onClick={() => pull(m.id)} disabled={!!pulling} className="shrink-0 rounded-md bg-accent px-3 py-1.5 text-xs font-medium text-accent-text disabled:opacity-60">
+                          <button type="button" onClick={() => pull(m.id)} disabled={!!pulling} className="shrink-0 rounded-md bg-accent px-3 py-1.5 text-xs font-medium text-accent-text disabled:opacity-60">
                             {isPulling ? 'Pulling…' : 'Pull'}
                           </button>
                         )}
@@ -526,7 +526,7 @@ function LlmParsingConfig({ addon }: { addon: Addon }) {
           )}
         </section>
 
-        <button onClick={save} disabled={saving} className="rounded-lg bg-accent px-4 py-2 text-sm font-medium text-accent-text transition-opacity disabled:opacity-60">
+        <button type="button" onClick={save} disabled={saving} className="rounded-lg bg-accent px-4 py-2 text-sm font-medium text-accent-text transition-opacity disabled:opacity-60">
           {saving ? 'Saving…' : 'Save'}
         </button>
       </div>
@@ -589,7 +589,7 @@ function AddonRow({ addon, onToggle, t, nameOverride, descriptionOverride, statu
           {isComingSoon ? t('admin.addons.disabled') : enabledState ? t('admin.addons.enabled') : t('admin.addons.disabled')}
         </span>
         {!hideToggle && (
-          <button
+          <button type="button"
             onClick={() => !isComingSoon && onToggle(addon)}
             disabled={isComingSoon}
             className="relative inline-flex h-6 w-11 items-center rounded-full transition-colors"
diff --git a/client/src/components/Admin/AdminMcpTokensPanel.tsx b/client/src/components/Admin/AdminMcpTokensPanel.tsx
index 060332ac0..e2c55c86a 100644
--- a/client/src/components/Admin/AdminMcpTokensPanel.tsx
+++ b/client/src/components/Admin/AdminMcpTokensPanel.tsx
@@ -126,13 +126,13 @@ export default function AdminMcpTokensPanel() {
                           </span>
                         ))}
                         {!expanded && hidden > 0 && (
-                          <button onClick={() => toggleScopes(session.id)}
+                          <button type="button" onClick={() => toggleScopes(session.id)}
                             className="inline-flex items-center px-1.5 py-0.5 rounded text-xs font-medium transition-colors hover:opacity-80 bg-surface-secondary text-content-secondary border border-edge">
                             +{hidden} more
                           </button>
                         )}
                         {expanded && hidden > 0 && (
-                          <button onClick={() => toggleScopes(session.id)}
+                          <button type="button" onClick={() => toggleScopes(session.id)}
                             className="inline-flex items-center px-1.5 py-0.5 rounded text-xs font-medium transition-colors hover:opacity-80 bg-surface-secondary text-content-secondary border border-edge">
                             show less
                           </button>
@@ -146,7 +146,7 @@ export default function AdminMcpTokensPanel() {
                     <span className="text-xs whitespace-nowrap text-right pt-0.5" style={{ color: 'var(--text-tertiary)' }}>
                       {new Date(session.created_at).toLocaleDateString(locale)}
                     </span>
-                    <button onClick={() => setRevokeConfirmId(session.id)}
+                    <button type="button" onClick={() => setRevokeConfirmId(session.id)}
                       className="p-1.5 rounded-lg transition-colors hover:bg-red-50 hover:text-red-600 dark:hover:bg-red-900/20"
                       style={{ color: 'var(--text-tertiary)' }} title={t('common.delete')}>
                       <Trash2 className="w-4 h-4" />
@@ -199,7 +199,7 @@ export default function AdminMcpTokensPanel() {
                   <span className="text-xs whitespace-nowrap text-right" style={{ color: 'var(--text-tertiary)' }}>
                     {token.last_used_at ? new Date(token.last_used_at).toLocaleDateString(locale) : t('admin.mcpTokens.never')}
                   </span>
-                  <button onClick={() => setDeleteConfirmId(token.id)}
+                  <button type="button" onClick={() => setDeleteConfirmId(token.id)}
                     className="p-1.5 rounded-lg transition-colors hover:bg-red-50 hover:text-red-600 dark:hover:bg-red-900/20"
                     style={{ color: 'var(--text-tertiary)' }} title={t('common.delete')}>
                     <Trash2 className="w-4 h-4" />
@@ -219,11 +219,11 @@ export default function AdminMcpTokensPanel() {
             <h3 className="text-base font-semibold text-content">{t('admin.oauthSessions.revokeTitle')}</h3>
             <p className="text-sm text-content-secondary">{t('admin.oauthSessions.revokeMessage')}</p>
             <div className="flex gap-2 justify-end">
-              <button onClick={() => setRevokeConfirmId(null)}
+              <button type="button" onClick={() => setRevokeConfirmId(null)}
                 className="px-4 py-2 rounded-lg text-sm border border-edge text-content-secondary">
                 {t('common.cancel')}
               </button>
-              <button onClick={() => handleRevoke(revokeConfirmId)}
+              <button type="button" onClick={() => handleRevoke(revokeConfirmId)}
                 className="px-4 py-2 rounded-lg text-sm font-medium text-white bg-red-600 hover:bg-red-700">
                 {t('common.delete')}
               </button>
@@ -240,11 +240,11 @@ export default function AdminMcpTokensPanel() {
             <h3 className="text-base font-semibold text-content">{t('admin.mcpTokens.deleteTitle')}</h3>
             <p className="text-sm text-content-secondary">{t('admin.mcpTokens.deleteMessage')}</p>
             <div className="flex gap-2 justify-end">
-              <button onClick={() => setDeleteConfirmId(null)}
+              <button type="button" onClick={() => setDeleteConfirmId(null)}
                 className="px-4 py-2 rounded-lg text-sm border border-edge text-content-secondary">
                 {t('common.cancel')}
               </button>
-              <button onClick={() => handleDelete(deleteConfirmId)}
+              <button type="button" onClick={() => handleDelete(deleteConfirmId)}
                 className="px-4 py-2 rounded-lg text-sm font-medium text-white bg-red-600 hover:bg-red-700">
                 {t('common.delete')}
               </button>
diff --git a/client/src/components/Admin/AdminPluginsPanel.tsx b/client/src/components/Admin/AdminPluginsPanel.tsx
index 4ca8ae1f1..b0c468d65 100644
--- a/client/src/components/Admin/AdminPluginsPanel.tsx
+++ b/client/src/components/Admin/AdminPluginsPanel.tsx
@@ -187,7 +187,7 @@ const PERM_KEYS = PLUGIN_PERMISSIONS
 const KNOWN_TYPES = ['widget', 'page', 'integration', 'trip-page']
 
 function isNewer(a: string, b: string): boolean {
-  const nums = (v: string) => v.split('-')[0].split('.').map(n => parseInt(n, 10) || 0)
+  const nums = (v: string) => v.split('-')[0].split('.').map(n => Number.parseInt(n, 10) || 0)
   const pa = nums(a), pb = nums(b)
   for (let i = 0; i < 3; i++) {
     const x = pa[i] || 0, y = pb[i] || 0
@@ -795,11 +795,11 @@ export default function AdminPluginsPanel() {
               <SegBtn active={view === 'discover'} onClick={openDiscover} label={t('admin.plugins.tabDiscover')} count={registry?.length} />
             </div>
             <div className="sm:hidden flex items-center gap-2 shrink-0">
-              <button onClick={pickUpload} title={t('admin.plugins.upload')}
+              <button type="button" onClick={pickUpload} title={t('admin.plugins.upload')}
                 className="h-[38px] w-[38px] grid place-items-center rounded-xl border border-edge bg-surface-card text-content-muted hover:text-content hover:border-content-faint transition-colors">
                 <UploadCloud size={15} />
               </button>
-              <button onClick={rescan} title={t('admin.plugins.rescan')}
+              <button type="button" onClick={rescan} title={t('admin.plugins.rescan')}
                 className="h-[38px] w-[38px] grid place-items-center rounded-xl border border-edge bg-surface-card text-content-muted hover:text-content hover:border-content-faint transition-colors">
                 <RefreshCw size={15} />
               </button>
@@ -842,11 +842,11 @@ export default function AdminPluginsPanel() {
               valueLabel={sortLabel(sort, t)}
               onPick={v => setSort(v as SortKey)} />
 
-            <button onClick={pickUpload} title={t('admin.plugins.upload')}
+            <button type="button" onClick={pickUpload} title={t('admin.plugins.upload')}
               className="hidden sm:grid h-[38px] w-[38px] place-items-center rounded-xl border border-edge bg-surface-card text-content-muted hover:text-content hover:border-content-faint transition-colors">
               <UploadCloud size={15} />
             </button>
-            <button onClick={rescan} title={t('admin.plugins.rescan')}
+            <button type="button" onClick={rescan} title={t('admin.plugins.rescan')}
               className="hidden sm:grid h-[38px] w-[38px] place-items-center rounded-xl border border-edge bg-surface-card text-content-muted hover:text-content hover:border-content-faint transition-colors">
               <RefreshCw size={15} />
             </button>
@@ -871,7 +871,7 @@ export default function AdminPluginsPanel() {
               <div className="mx-1.5 sm:mx-3 mb-2 mt-1 flex items-center gap-2.5 px-3.5 py-2.5 rounded-xl bg-warning-soft border border-warning/30">
                 <ArrowUpCircle size={16} className="text-warning shrink-0" />
                 <span className="text-xs text-content-secondary">{t('admin.plugins.updatesAvailable', { count: updatable.length })}</span>
-                <button onClick={() => void updateAll()}
+                <button type="button" onClick={() => void updateAll()}
                   className="ml-auto text-xs font-semibold px-3 py-1.5 rounded-lg bg-warning text-white hover:opacity-90 transition-opacity">
                   {t('admin.plugins.updateAll')}
                 </button>
@@ -913,7 +913,7 @@ export default function AdminPluginsPanel() {
           <div className="bg-surface-card border border-edge rounded-2xl w-full max-w-2xl max-h-[70vh] flex flex-col shadow-modal" onClick={e => e.stopPropagation()}>
             <div className="px-5 py-3.5 border-b border-edge-secondary flex items-center justify-between">
               <span className="text-sm font-semibold text-content flex items-center gap-2"><Bug size={15} /> {errorsFor.id} — {t('admin.plugins.errorLog')}</span>
-              <button onClick={() => setErrorsFor(null)} className="text-content-faint hover:text-content"><X size={16} /></button>
+              <button type="button" onClick={() => setErrorsFor(null)} className="text-content-faint hover:text-content"><X size={16} /></button>
             </div>
             <div className="p-4 overflow-y-auto text-xs font-mono">
               {errorsFor.rows.length === 0 ? <p className="text-content-faint py-4 text-center">{t('admin.plugins.noErrors')}</p> :
@@ -935,7 +935,7 @@ export default function AdminPluginsPanel() {
           <div className="bg-surface-card border border-edge rounded-2xl w-full max-w-lg shadow-modal" onClick={e => e.stopPropagation()}>
             <div className="px-5 py-3.5 border-b border-edge-secondary flex items-center justify-between">
               <span className="text-sm font-semibold text-content flex items-center gap-2"><Globe size={15} /> {egressFor.id} — {t('admin.plugins.allowedHosts')}</span>
-              <button onClick={() => setEgressFor(null)} className="text-content-faint hover:text-content"><X size={16} /></button>
+              <button type="button" onClick={() => setEgressFor(null)} className="text-content-faint hover:text-content"><X size={16} /></button>
             </div>
             <div className="p-5 space-y-3">
               {!egressFor.supported ? (
@@ -949,7 +949,7 @@ export default function AdminPluginsPanel() {
                   {egressFor.hosts.map(h => (
                     <div key={h} className="flex items-center justify-between gap-2 rounded-lg border border-edge-secondary px-3 py-2">
                       <span className="text-sm font-mono text-content break-all">{h}</span>
-                      <button
+                      <button type="button"
                         disabled={egressSaving}
                         onClick={() => saveEgress(egressFor.hosts.filter(x => x !== h))}
                         className="text-content-faint hover:text-danger disabled:opacity-50"
@@ -964,7 +964,7 @@ export default function AdminPluginsPanel() {
                       placeholder="gotify.example.com"
                       className="flex-1 rounded-lg border border-edge bg-surface px-3 py-2 text-sm text-content"
                     />
-                    <button
+                    <button type="button"
                       disabled={egressSaving || !egressDraft.trim()}
                       onClick={() => saveEgress([...egressFor.hosts, egressDraft.trim()])}
                       className="rounded-lg bg-content px-3 py-2 text-sm text-surface disabled:opacity-50"
@@ -1043,7 +1043,7 @@ function sortLabel(s: SortKey, t: T): string {
 
 function SegBtn({ active, onClick, label, count }: { active: boolean; onClick: () => void; label: string; count?: number }) {
   return (
-    <button onClick={onClick} role="tab" aria-selected={active}
+    <button type="button" onClick={onClick} role="tab" aria-selected={active}
       className={`inline-flex items-center gap-2 text-[13px] font-medium px-3.5 py-1.5 rounded-lg transition-colors ${
         active ? 'bg-surface-card text-content shadow-card' : 'text-content-muted hover:text-content'}`}>
       {label}
@@ -1064,7 +1064,7 @@ function FilterMenu({ id, label, valueLabel, options, onPick, value, menu, setMe
   const active = value !== options[0]?.[0]
   return (
     <div className="relative">
-      <button onClick={() => setMenu(open ? null : id)} title={`${label}: ${valueLabel}`}
+      <button type="button" onClick={() => setMenu(open ? null : id)} title={`${label}: ${valueLabel}`}
         className={`relative h-[38px] w-[38px] sm:w-auto px-0 sm:px-3 inline-flex items-center justify-center sm:justify-start gap-1.5 rounded-xl border bg-surface-card text-[13px] text-content-secondary transition-colors whitespace-nowrap hover:border-content-faint ${
           active ? 'border-content-faint' : 'border-edge'}`}>
         {icon}
@@ -1076,7 +1076,7 @@ function FilterMenu({ id, label, valueLabel, options, onPick, value, menu, setMe
       {open && (
         <div className="absolute top-11 right-0 z-30 min-w-[180px] max-w-[calc(100vw-2rem)] p-1.5 rounded-xl border border-edge bg-surface-card shadow-elevated">
           {options.map(([v, lbl]) => (
-            <button key={v} onClick={() => { onPick(v); setMenu(null) }}
+            <button type="button" key={v} onClick={() => { onPick(v); setMenu(null) }}
               className={`w-full flex items-center gap-2.5 px-2.5 py-2 rounded-lg text-[13px] transition-colors hover:bg-surface-tertiary ${
                 value === v ? 'text-content font-semibold' : 'text-content-secondary'}`}>
               {lbl}<Check size={15} className={`ml-auto text-accent ${value === v ? 'opacity-100' : 'opacity-0'}`} />
@@ -1095,7 +1095,7 @@ function EmptyState({ t, onDiscover }: { t: T; onDiscover: () => void }) {
         <PackageOpen size={26} className="text-content-faint" />
       </div>
       <p className="text-sm font-medium text-content-muted">{t('admin.plugins.empty')}</p>
-      <button onClick={onDiscover} className="mt-4 inline-flex items-center gap-1.5 text-xs font-semibold px-4 py-2 rounded-lg bg-accent text-accent-text">
+      <button type="button" onClick={onDiscover} className="mt-4 inline-flex items-center gap-1.5 text-xs font-semibold px-4 py-2 rounded-lg bg-accent text-accent-text">
         <Download size={14} /> {t('admin.plugins.tabDiscover')}
       </button>
     </div>
@@ -1158,7 +1158,7 @@ function InstalledRow({ p, t, busy, menu, setMenu, hasUpdate, latestVer, blocked
           <div className="flex items-center gap-1.5 mt-1.5 text-[11.5px] text-warning">
             <ShieldAlert size={13} className="shrink-0" />
             <span className="truncate">{t('admin.plugins.updateBlocked', { reason: p.updateBlock.detail ?? p.updateBlock.code })}</span>
-            <button onClick={onReviewBlock}
+            <button type="button" onClick={onReviewBlock}
               className="shrink-0 font-semibold underline underline-offset-2 hover:opacity-80 transition-opacity">
               {t('admin.plugins.reviewBlock')}
             </button>
@@ -1181,7 +1181,7 @@ function InstalledRow({ p, t, busy, menu, setMenu, hasUpdate, latestVer, blocked
                 Actionable, and warning-toned until at least one host exists, because
                 until then the plugin cannot reach anything and looks silently broken. */}
             {p.operatorEgress && (
-              <button
+              <button type="button"
                 onClick={onEgress}
                 title={t('admin.plugins.allowedHosts.hint')}
                 className={`inline-flex items-center gap-1.5 text-[11px] font-medium px-2 py-[3px] rounded-md border transition-colors ${
@@ -1211,7 +1211,7 @@ function InstalledRow({ p, t, busy, menu, setMenu, hasUpdate, latestVer, blocked
 
       <div className="flex items-center gap-1.5 sm:gap-2 shrink-0">
         {hasUpdate && (
-          <button onClick={onUpdate} disabled={busy === p.id} title={t('admin.plugins.updateTo', { version: latestVer })}
+          <button type="button" onClick={onUpdate} disabled={busy === p.id} title={t('admin.plugins.updateTo', { version: latestVer })}
             className="inline-flex items-center gap-1.5 text-[11.5px] font-semibold px-2 sm:px-2.5 py-1.5 rounded-full text-warning bg-warning-soft border border-warning/30 hover:opacity-90 transition-opacity disabled:opacity-50">
             <ArrowUpCircle size={13} /> <span className="hidden sm:inline">{t('admin.plugins.updateTo', { version: latestVer })}</span>
           </button>
@@ -1221,7 +1221,7 @@ function InstalledRow({ p, t, busy, menu, setMenu, hasUpdate, latestVer, blocked
         </span>
         <ToggleSwitch on={p.enabled === 1} label={t('admin.plugins.enabledToggle')} onToggle={onToggle} />
         <div className="relative">
-          <button ref={menuBtnRef} data-testid={`plugin-row-menu-btn-${p.id}`} onClick={() => setMenu(menuOpen ? null : `row:${p.id}`)}
+          <button type="button" ref={menuBtnRef} data-testid={`plugin-row-menu-btn-${p.id}`} onClick={() => setMenu(menuOpen ? null : `row:${p.id}`)}
             className="w-[34px] h-[34px] grid place-items-center rounded-lg text-content-faint hover:text-content hover:bg-surface-tertiary transition-colors">
             <MoreHorizontal size={17} />
           </button>
@@ -1275,7 +1275,7 @@ function anchorMenu(trigger: HTMLElement | null): CSSProperties {
 
 function MenuItem({ icon, label, onClick, danger }: { icon: React.ReactNode; label: string; onClick: () => void; danger?: boolean }) {
   return (
-    <button onClick={onClick}
+    <button type="button" onClick={onClick}
       className={`w-full flex items-center gap-2.5 px-2.5 py-2 rounded-lg text-[13px] transition-colors ${
         danger ? 'text-danger hover:bg-danger-soft' : 'text-content-secondary hover:bg-surface-tertiary'}`}>
       {icon} {label}
@@ -1349,7 +1349,7 @@ function RegistryGrid({ items, onInstall, onOpenDetail, busy, t, installedIds, f
                     <Download size={11} /> {formatCompactCount(item.downloadCount)}
                   </span>
                 )}
-                <button onClick={e => { e.stopPropagation(); onInstall(item.id, offer.version) }}
+                <button type="button" onClick={e => { e.stopPropagation(); onInstall(item.id, offer.version) }}
                   disabled={busy === item.id || installed || offer.blocked}
                   title={installed ? undefined : offer.title}
                   className="ml-auto text-xs font-semibold px-3.5 py-1.5 rounded-lg bg-accent text-accent-text hover:bg-accent-hover disabled:opacity-50 disabled:bg-surface-tertiary disabled:text-content-faint transition-colors">
@@ -1412,7 +1412,7 @@ function PluginDetailModal({ item, installed, busy, onInstall, onClose, t, local
         <div className="relative">
           <Screenshot url={item.screenshotUrl} className="w-full aspect-[16/9]" iconSize={36} />
           <div className="absolute inset-0 bg-gradient-to-t from-black/50 to-transparent" />
-          <button onClick={onClose} className="absolute top-3 right-3 w-8 h-8 grid place-items-center rounded-lg bg-black/40 text-white hover:bg-black/60 transition-colors"><X size={16} /></button>
+          <button type="button" onClick={onClose} className="absolute top-3 right-3 w-8 h-8 grid place-items-center rounded-lg bg-black/40 text-white hover:bg-black/60 transition-colors"><X size={16} /></button>
         </div>
 
         <div className="flex items-start gap-3 sm:gap-3.5 px-4 sm:px-5 -mt-7 relative z-[1]">
@@ -1426,7 +1426,7 @@ function PluginDetailModal({ item, installed, busy, onInstall, onClose, t, local
             </div>
             <p className="text-[12.5px] text-content-faint mt-0.5">{item.author}{item.latest ? ` · v${item.latest}` : ''}</p>
           </div>
-          <button onClick={() => onInstall(item.id, offer.version)}
+          <button type="button" onClick={() => onInstall(item.id, offer.version)}
             disabled={busy === item.id || installed || offer.blocked}
             title={installed ? undefined : offer.title}
             className="self-end text-[13px] font-semibold px-3 sm:px-4 py-2 rounded-lg bg-accent text-accent-text hover:bg-accent-hover disabled:opacity-50 disabled:bg-surface-tertiary disabled:text-content-faint transition-colors shrink-0">
@@ -1606,12 +1606,12 @@ function SignatureBlockDialog({ data, entry, busy, t, onRetrust, onClose }: {
           )}
         </div>
         <div className="px-5 py-3.5 border-t border-edge-secondary bg-surface-secondary flex items-center justify-end gap-2">
-          <button onClick={onClose}
+          <button type="button" onClick={onClose}
             className="text-xs font-medium px-3.5 py-2 rounded-lg border border-edge text-content-muted hover:text-content hover:bg-surface-tertiary transition-colors">
             {offerRetrust ? t('admin.plugins.sig.cancel') : t('common.close')}
           </button>
           {offerRetrust && (
-            <button onClick={() => onRetrust(version, newKey)} disabled={busy}
+            <button type="button" onClick={() => onRetrust(version, newKey)} disabled={busy}
               className="text-xs font-semibold px-4 py-2 rounded-lg bg-warning text-white hover:opacity-90 transition-opacity disabled:opacity-50">
               {t('admin.plugins.sig.retrustConfirm')}
             </button>
@@ -1685,8 +1685,8 @@ function UpdateConsentDialog({ data, unsigned, t, onApprove, onLater }: {
           )}
         </div>
         <div className="px-5 py-3.5 border-t border-edge-secondary bg-surface-secondary flex items-center justify-end gap-2">
-          <button onClick={onLater} className="text-xs font-medium px-3.5 py-2 rounded-lg border border-edge text-content-muted hover:text-content hover:bg-surface-tertiary transition-colors">{t('admin.plugins.updateLater')}</button>
-          <button onClick={onApprove} className="text-xs font-semibold px-4 py-2 rounded-lg bg-accent text-accent-text hover:bg-accent-hover transition-colors">{t('admin.plugins.updateApprove')}</button>
+          <button type="button" onClick={onLater} className="text-xs font-medium px-3.5 py-2 rounded-lg border border-edge text-content-muted hover:text-content hover:bg-surface-tertiary transition-colors">{t('admin.plugins.updateLater')}</button>
+          <button type="button" onClick={onApprove} className="text-xs font-semibold px-4 py-2 rounded-lg bg-accent text-accent-text hover:bg-accent-hover transition-colors">{t('admin.plugins.updateApprove')}</button>
         </div>
       </div>
     </div>
@@ -1726,7 +1726,7 @@ function DependencyResolveDialog({ data, t, busy, installedIds, onDownload, onCl
                     : t('admin.plugins.dep.requires', { version: r.constraint })}
                 </div>
               </div>
-              <button onClick={() => onDownload(r.id, r.constraint)} disabled={busy}
+              <button type="button" onClick={() => onDownload(r.id, r.constraint)} disabled={busy}
                 className="inline-flex items-center gap-1.5 text-[11.5px] font-semibold px-3 py-1.5 rounded-full bg-accent text-accent-text hover:bg-accent-hover transition-colors disabled:opacity-50 shrink-0">
                 <Download size={13} /> {r.installed ? t('admin.plugins.dep.update') : t('admin.plugins.dep.download')}
               </button>
@@ -1737,7 +1737,7 @@ function DependencyResolveDialog({ data, t, busy, installedIds, onDownload, onCl
           )}
         </div>
         <div className="px-5 py-3.5 border-t border-edge-secondary bg-surface-secondary flex items-center justify-end">
-          <button onClick={onClose} className="text-xs font-medium px-3.5 py-2 rounded-lg border border-edge text-content-muted hover:text-content hover:bg-surface-tertiary transition-colors">{t('common.cancel')}</button>
+          <button type="button" onClick={onClose} className="text-xs font-medium px-3.5 py-2 rounded-lg border border-edge text-content-muted hover:text-content hover:bg-surface-tertiary transition-colors">{t('common.cancel')}</button>
         </div>
       </div>
     </div>
@@ -1763,7 +1763,7 @@ function SecurityInfo({ t }: { t: T }) {
         <ShieldCheck size={14} className="text-content-faint shrink-0 mt-0.5" />
         <p className="text-xs text-content-muted">{t('admin.plugins.reviewedMeaning')}</p>
       </div>
-      <button onClick={() => setOpen(o => !o)}
+      <button type="button" onClick={() => setOpen(o => !o)}
         className="w-full px-4 sm:px-6 py-2.5 border-t border-edge-secondary flex items-center justify-between gap-2 text-xs font-medium text-content-secondary hover:text-content hover:bg-surface-tertiary transition-colors">
         <span className="flex items-center gap-2"><Lock size={13} className="shrink-0" /> <span className="text-left">{t('admin.plugins.security.title')}</span></span>
         <ChevronDown size={15} className={`shrink-0 transition-transform ${open ? 'rotate-180' : ''}`} />
diff --git a/client/src/components/Admin/BackupPanel.tsx b/client/src/components/Admin/BackupPanel.tsx
index e7d18f1a8..754cd276a 100644
--- a/client/src/components/Admin/BackupPanel.tsx
+++ b/client/src/components/Admin/BackupPanel.tsx
@@ -191,7 +191,7 @@ export default function BackupPanel() {
             </div>
           </div>
           <div className="flex items-center gap-2">
-            <button
+            <button type="button"
               onClick={loadBackups}
               disabled={isLoading}
               className="p-2 text-gray-500 hover:bg-gray-100 rounded-lg transition-colors"
@@ -208,7 +208,7 @@ export default function BackupPanel() {
               className="hidden"
               onChange={handleUploadRestore}
             />
-            <button
+            <button type="button"
               onClick={() => fileInputRef.current?.click()}
               disabled={isUploading}
               className="flex items-center gap-2 border border-gray-200 text-gray-700 px-3 py-2 rounded-lg hover:bg-gray-50 text-sm font-medium disabled:opacity-60"
@@ -222,7 +222,7 @@ export default function BackupPanel() {
               <span className="hidden sm:inline">{isUploading ? t('backup.uploading') : t('backup.upload')}</span>
             </button>
 
-            <button
+            <button type="button"
               onClick={handleCreate}
               disabled={isCreating}
               className="flex items-center gap-2 bg-slate-900 dark:bg-slate-100 text-white dark:text-slate-900 px-3 sm:px-4 py-2 rounded-lg hover:bg-slate-900 text-sm font-medium disabled:opacity-60"
@@ -247,7 +247,7 @@ export default function BackupPanel() {
           <div className="text-center py-12 text-gray-400">
             <HardDrive className="w-10 h-10 mb-3 mx-auto opacity-40" />
             <p className="text-sm">{t('backup.empty')}</p>
-            <button onClick={handleCreate} className="mt-4 text-slate-700 text-sm hover:underline">
+            <button type="button" onClick={handleCreate} className="mt-4 text-slate-700 text-sm hover:underline">
               {t('backup.createFirst')}
             </button>
           </div>
@@ -274,14 +274,14 @@ export default function BackupPanel() {
                   </div>
                 </div>
                 <div className="flex items-center gap-1.5 flex-shrink-0">
-                  <button
+                  <button type="button"
                     onClick={() => backupApi.download(backup.filename).catch(() => toast.error(t('backup.toast.downloadError')))}
                     className="flex items-center gap-1.5 px-3 py-1.5 text-xs text-slate-700 border border-slate-200 rounded-lg hover:bg-slate-50"
                   >
                     <Download className="w-3.5 h-3.5" />
                     {t('backup.download')}
                   </button>
-                  <button
+                  <button type="button"
                     onClick={() => handleRestore(backup.filename)}
                     disabled={restoringFile === backup.filename}
                     className="flex items-center gap-1.5 px-3 py-1.5 text-xs text-amber-700 border border-amber-200 rounded-lg hover:bg-amber-50 disabled:opacity-60"
@@ -292,7 +292,7 @@ export default function BackupPanel() {
                     }
                     {t('backup.restore')}
                   </button>
-                  <button
+                  <button type="button"
                     onClick={() => handleDelete(backup.filename)}
                     className="p-1.5 text-gray-400 hover:text-red-600 hover:bg-red-50 rounded-lg"
                   >
@@ -322,7 +322,7 @@ export default function BackupPanel() {
               <span className="text-sm font-medium text-gray-900">{t('backup.auto.enable')}</span>
               <p className="text-xs text-gray-500 mt-0.5">{t('backup.auto.enableHint')}</p>
             </div>
-            <button
+            <button type="button"
               onClick={() => handleAutoSettingsChange('enabled', !autoSettings.enabled)}
               className="relative shrink-0 inline-flex h-6 w-11 items-center rounded-full transition-colors"
               style={{ background: autoSettings.enabled ? 'var(--text-primary)' : 'var(--border-primary)' }}
@@ -339,7 +339,7 @@ export default function BackupPanel() {
                 <label className="block text-sm font-medium text-gray-700 mb-2">{t('backup.auto.interval')}</label>
                 <div className="flex flex-wrap gap-2">
                   {INTERVAL_OPTIONS.map(opt => (
-                    <button
+                    <button type="button"
                       key={opt.value}
                       onClick={() => handleAutoSettingsChange('interval', opt.value)}
                       className={`px-4 py-2 rounded-lg text-sm font-medium border transition-colors ${
@@ -360,7 +360,7 @@ export default function BackupPanel() {
                   <label className="block text-sm font-medium text-gray-700 mb-2">{t('backup.auto.hour')}</label>
                   <CustomSelect
                     value={String(autoSettings.hour)}
-                    onChange={v => handleAutoSettingsChange('hour', parseInt(String(v), 10))}
+                    onChange={v => handleAutoSettingsChange('hour', Number.parseInt(String(v), 10))}
                     size="sm"
                     options={HOURS.map(h => {
                       let label: string
@@ -386,7 +386,7 @@ export default function BackupPanel() {
                   <label className="block text-sm font-medium text-gray-700 mb-2">{t('backup.auto.dayOfWeek')}</label>
                   <div className="flex flex-wrap gap-2">
                     {DAYS_OF_WEEK.map(opt => (
-                      <button
+                      <button type="button"
                         key={opt.value}
                         onClick={() => handleAutoSettingsChange('day_of_week', opt.value)}
                         className={`px-3 py-2 rounded-lg text-sm font-medium border transition-colors ${
@@ -408,7 +408,7 @@ export default function BackupPanel() {
                   <label className="block text-sm font-medium text-gray-700 mb-2">{t('backup.auto.dayOfMonth')}</label>
                   <CustomSelect
                     value={String(autoSettings.day_of_month)}
-                    onChange={v => handleAutoSettingsChange('day_of_month', parseInt(String(v), 10))}
+                    onChange={v => handleAutoSettingsChange('day_of_month', Number.parseInt(String(v), 10))}
                     size="sm"
                     options={DAYS_OF_MONTH.map(d => ({ value: String(d), label: String(d) }))}
                   />
@@ -421,7 +421,7 @@ export default function BackupPanel() {
                 <label className="block text-sm font-medium text-gray-700 mb-2">{t('backup.auto.keepLabel')}</label>
                 <div className="flex flex-wrap gap-2">
                   {KEEP_OPTIONS.map(opt => (
-                    <button
+                    <button type="button"
                       key={opt.value}
                       onClick={() => handleAutoSettingsChange('keep_days', opt.value)}
                       className={`px-4 py-2 rounded-lg text-sm font-medium border transition-colors ${
@@ -440,7 +440,7 @@ export default function BackupPanel() {
 
           {/* Save button */}
           <div className="flex justify-end pt-2 border-t border-gray-100">
-            <button
+            <button type="button"
               onClick={handleSaveAutoSettings}
               disabled={autoSettingsSaving || !autoSettingsDirty}
               className="flex items-center gap-2 bg-slate-900 dark:bg-slate-100 text-white dark:text-slate-900 px-5 py-2 rounded-lg hover:bg-slate-900 text-sm font-medium disabled:opacity-50 transition-colors"
@@ -497,14 +497,14 @@ export default function BackupPanel() {
 
             {/* Footer */}
             <div style={{ padding: '0 24px 20px', display: 'flex', gap: 10, justifyContent: 'flex-end' }}>
-              <button
+              <button type="button"
                 onClick={() => setRestoreConfirm(null)}
                 className="text-gray-600 dark:text-gray-400 hover:bg-gray-100 dark:hover:bg-gray-700"
                 style={{ padding: '9px 20px', borderRadius: 10, fontSize: 'calc(13px * var(--fs-scale-body, 1))', fontWeight: 600, border: 'none', cursor: 'pointer', fontFamily: 'inherit' }}
               >
                 {t('common.cancel')}
               </button>
-              <button
+              <button type="button"
                 onClick={executeRestore}
                 className="bg-[#dc2626] text-white"
                 style={{ padding: '9px 20px', borderRadius: 10, fontSize: 'calc(13px * var(--fs-scale-body, 1))', fontWeight: 600, border: 'none', cursor: 'pointer', fontFamily: 'inherit' }}
diff --git a/client/src/components/Admin/CategoryManager.tsx b/client/src/components/Admin/CategoryManager.tsx
index 6c68f4bc0..b26af8629 100644
--- a/client/src/components/Admin/CategoryManager.tsx
+++ b/client/src/components/Admin/CategoryManager.tsx
@@ -194,7 +194,7 @@ export default function CategoryManager() {
           <h2 className="font-semibold text-content">{t('categories.title')}</h2>
           <p className="text-xs mt-1 text-content-muted">{t('categories.subtitle')}</p>
         </div>
-        <button onClick={handleStartCreate}
+        <button type="button" onClick={handleStartCreate}
           className="flex items-center gap-2 bg-slate-900 text-white px-3 sm:px-4 py-2 rounded-lg hover:bg-slate-700 text-sm font-medium">
           <Plus className="w-4 h-4" />
           <span className="hidden sm:inline">{t('categories.new')}</span>
@@ -235,11 +235,11 @@ export default function CategoryManager() {
                       </div>
                     </div>
                     <div className="flex items-center gap-1 opacity-0 group-hover:opacity-100 transition-opacity">
-                      <button onClick={() => handleStartEdit(cat)}
+                      <button type="button" onClick={() => handleStartEdit(cat)}
                         className="p-1.5 text-gray-400 hover:text-slate-700 hover:bg-slate-100 rounded-lg">
                         <Edit2 className="w-4 h-4" />
                       </button>
-                      <button onClick={() => handleDelete(cat.id)}
+                      <button type="button" onClick={() => handleDelete(cat.id)}
                         className="p-1.5 text-gray-400 hover:text-red-600 hover:bg-red-50 rounded-lg">
                         <Trash2 className="w-4 h-4" />
                       </button>
diff --git a/client/src/components/Admin/DefaultUserSettingsTab.tsx b/client/src/components/Admin/DefaultUserSettingsTab.tsx
index 365303efa..a9bd11fc9 100644
--- a/client/src/components/Admin/DefaultUserSettingsTab.tsx
+++ b/client/src/components/Admin/DefaultUserSettingsTab.tsx
@@ -86,7 +86,7 @@ function OptionButton({
   children: React.ReactNode
 }) {
   return (
-    <button
+    <button type="button"
       onClick={onClick}
       style={{
         display: 'flex', alignItems: 'center', gap: 8,
@@ -154,7 +154,7 @@ export default function DefaultUserSettingsTab(): React.ReactElement {
 
   const ResetButton = ({ field }: { field: keyof Defaults }) =>
     isSet(field) ? (
-      <button
+      <button type="button"
         onClick={() => reset(field)}
         className="text-xs ml-2 text-content-faint underline"
         style={{ background: 'none', border: 'none', cursor: 'pointer' }}
diff --git a/client/src/components/Admin/DevNotificationsPanel.tsx b/client/src/components/Admin/DevNotificationsPanel.tsx
index 7237b23ae..baf8d0396 100644
--- a/client/src/components/Admin/DevNotificationsPanel.tsx
+++ b/client/src/components/Admin/DevNotificationsPanel.tsx
@@ -66,7 +66,7 @@ export default function DevNotificationsPanel(): React.ReactElement {
   }: {
     id: string; label: string; sub: string; icon: React.ElementType; color: string; onClick: () => void
   }) => (
-    <button
+    <button type="button"
       onClick={onClick}
       disabled={sending !== null}
       className="flex items-center gap-3 px-4 py-3 rounded-lg border transition-colors text-left w-full border-edge bg-surface-card"
diff --git a/client/src/components/Admin/GitHubPanel.tsx b/client/src/components/Admin/GitHubPanel.tsx
index 26774989e..fb54eb708 100644
--- a/client/src/components/Admin/GitHubPanel.tsx
+++ b/client/src/components/Admin/GitHubPanel.tsx
@@ -461,7 +461,7 @@ export default function GitHubPanel({ isPrerelease = false }: { isPrerelease?: b
                         {/* Expandable body */}
                         {release.body && (
                           <div className="mt-2">
-                            <button
+                            <button type="button"
                               onClick={() => toggleExpand(release.id)}
                               className="flex items-center gap-1 text-[11px] font-medium text-content-muted transition-colors"
                             >
@@ -484,7 +484,7 @@ export default function GitHubPanel({ isPrerelease = false }: { isPrerelease?: b
             {/* Load more */}
             {hasMore && (
               <div className="pt-2 text-center">
-                <button
+                <button type="button"
                   onClick={handleLoadMore}
                   disabled={loadingMore}
                   className="inline-flex items-center gap-2 rounded-lg bg-surface-secondary px-4 py-2 text-xs font-medium text-content-muted transition-colors"
diff --git a/client/src/components/Admin/PackingTemplateManager.tsx b/client/src/components/Admin/PackingTemplateManager.tsx
index 9773b1999..2baa7313f 100644
--- a/client/src/components/Admin/PackingTemplateManager.tsx
+++ b/client/src/components/Admin/PackingTemplateManager.tsx
@@ -158,7 +158,7 @@ export default function PackingTemplateManager() {
           <h2 className="font-semibold text-slate-900">{t('admin.packingTemplates.title')}</h2>
           <p className="text-xs text-slate-400 mt-1">{t('admin.packingTemplates.subtitle')}</p>
         </div>
-        <button onClick={() => setShowCreate(true)}
+        <button type="button" onClick={() => setShowCreate(true)}
           className="flex items-center gap-1.5 px-3 py-1.5 text-sm bg-slate-900 text-white rounded-lg hover:bg-slate-700 transition-colors">
           <Plus className="w-4 h-4" /> <span className="hidden sm:inline">{t('admin.packingTemplates.create')}</span>
         </button>
@@ -171,8 +171,8 @@ export default function PackingTemplateManager() {
           <input autoFocus value={createName} onChange={e => setCreateName(e.target.value)}
             onKeyDown={e => { if (e.key === 'Enter') handleCreateTemplate(); if (e.key === 'Escape') setShowCreate(false) }}
             placeholder={t('admin.packingTemplates.namePlaceholder')} className={inputStyle} />
-          <button onClick={handleCreateTemplate} className={`${btnIcon} text-slate-600 hover:text-slate-900`}><Check size={16} /></button>
-          <button onClick={() => setShowCreate(false)} className={`${btnIcon} text-slate-400 hover:text-slate-600`}><X size={16} /></button>
+          <button type="button" onClick={handleCreateTemplate} className={`${btnIcon} text-slate-600 hover:text-slate-900`}><Check size={16} /></button>
+          <button type="button" onClick={() => setShowCreate(false)} className={`${btnIcon} text-slate-400 hover:text-slate-600`}><X size={16} /></button>
         </div>
       )}
 
@@ -187,7 +187,7 @@ export default function PackingTemplateManager() {
             <div key={tmpl.id}>
               {/* Template row */}
               <div className="px-5 py-3 flex items-center gap-3 hover:bg-slate-50 transition-colors">
-                <button onClick={() => toggleExpand(tmpl.id)} className="text-slate-400 flex-shrink-0 p-0 bg-transparent border-none cursor-pointer">
+                <button type="button" onClick={() => toggleExpand(tmpl.id)} className="text-slate-400 flex-shrink-0 p-0 bg-transparent border-none cursor-pointer">
                   {expandedId === tmpl.id ? <ChevronDown size={15} /> : <ChevronRight size={15} />}
                 </button>
                 <Package size={16} className="text-slate-400 flex-shrink-0" />
@@ -202,9 +202,9 @@ export default function PackingTemplateManager() {
                 <span className="text-xs text-slate-400 px-2 py-0.5 bg-slate-100 rounded-full">
                   {tmpl.category_count} {t('admin.packingTemplates.categories')} · {tmpl.item_count} {t('admin.packingTemplates.items')}
                 </span>
-                <button onClick={() => { setEditingTemplate(tmpl.id); setEditTemplateName(tmpl.name) }}
+                <button type="button" onClick={() => { setEditingTemplate(tmpl.id); setEditTemplateName(tmpl.name) }}
                   className={`${btnIcon} hover:bg-slate-100 text-slate-400 hover:text-slate-700`}><Edit2 size={14} /></button>
-                <button onClick={() => handleDeleteTemplate(tmpl.id)}
+                <button type="button" onClick={() => handleDeleteTemplate(tmpl.id)}
                   className={`${btnIcon} hover:bg-red-50 text-slate-400 hover:text-red-500`}><Trash2 size={14} /></button>
               </div>
 
@@ -228,11 +228,11 @@ export default function PackingTemplateManager() {
                             <span className="flex-1 text-xs font-bold text-slate-500 uppercase tracking-wider">{cat.name}</span>
                           )}
                           <span className="text-xs text-slate-400">{catItems.length}</span>
-                          <button onClick={() => { setAddingItemToCatId(addingItemToCatId === cat.id ? null : cat.id); setNewItemName(''); setTimeout(() => addItemRef.current?.focus(), 30) }}
+                          <button type="button" onClick={() => { setAddingItemToCatId(addingItemToCatId === cat.id ? null : cat.id); setNewItemName(''); setTimeout(() => addItemRef.current?.focus(), 30) }}
                             className={`${btnIcon} text-slate-400 hover:text-slate-700`}><Plus size={13} /></button>
-                          <button onClick={() => { setEditingCatId(cat.id); setEditCatName(cat.name) }}
+                          <button type="button" onClick={() => { setEditingCatId(cat.id); setEditCatName(cat.name) }}
                             className={`${btnIcon} text-slate-400 hover:text-slate-700`}><Edit2 size={13} /></button>
-                          <button onClick={() => handleDeleteCategory(cat.id)}
+                          <button type="button" onClick={() => handleDeleteCategory(cat.id)}
                             className={`${btnIcon} text-slate-400 hover:text-red-500`}><Trash2 size={13} /></button>
                         </div>
 
@@ -246,15 +246,15 @@ export default function PackingTemplateManager() {
                                     <input autoFocus value={editItemName} onChange={e => setEditItemName(e.target.value)}
                                       onKeyDown={e => { if (e.key === 'Enter') handleRenameItem(item.id); if (e.key === 'Escape') setEditingItemId(null) }}
                                       className="flex-1 px-2 py-1 border border-slate-200 rounded-lg text-sm" />
-                                    <button onClick={() => handleRenameItem(item.id)} className="p-1 text-slate-600 hover:text-slate-900"><Check size={13} /></button>
-                                    <button onClick={() => setEditingItemId(null)} className="p-1 text-slate-400"><X size={13} /></button>
+                                    <button type="button" onClick={() => handleRenameItem(item.id)} className="p-1 text-slate-600 hover:text-slate-900"><Check size={13} /></button>
+                                    <button type="button" onClick={() => setEditingItemId(null)} className="p-1 text-slate-400"><X size={13} /></button>
                                   </>
                                 ) : (
                                   <>
                                     <span className="flex-1 text-sm text-slate-700">{item.name}</span>
-                                    <button onClick={() => { setEditingItemId(item.id); setEditItemName(item.name) }}
+                                    <button type="button" onClick={() => { setEditingItemId(item.id); setEditItemName(item.name) }}
                                       className="p-1 rounded opacity-0 group-hover:opacity-100 text-slate-400 hover:text-slate-700 transition-all"><Edit2 size={12} /></button>
-                                    <button onClick={() => handleDeleteItem(item.id)}
+                                    <button type="button" onClick={() => handleDeleteItem(item.id)}
                                       className="p-1 rounded opacity-0 group-hover:opacity-100 text-slate-400 hover:text-red-500 transition-all"><Trash2 size={12} /></button>
                                   </>
                                 )}
@@ -268,9 +268,9 @@ export default function PackingTemplateManager() {
                                   onKeyDown={e => { if (e.key === 'Enter' && newItemName.trim()) handleAddItem(cat.id); if (e.key === 'Escape') { setAddingItemToCatId(null); setNewItemName('') } }}
                                   placeholder={t('admin.packingTemplates.itemName')}
                                   className="flex-1 px-2 py-1 border border-slate-200 rounded-lg text-sm" />
-                                <button onClick={() => handleAddItem(cat.id)} disabled={!newItemName.trim()}
+                                <button type="button" onClick={() => handleAddItem(cat.id)} disabled={!newItemName.trim()}
                                   className="p-1.5 rounded-lg bg-slate-900 text-white disabled:bg-slate-300 hover:bg-slate-700 transition-colors"><Plus size={13} /></button>
-                                <button onClick={() => { setAddingItemToCatId(null); setNewItemName('') }}
+                                <button type="button" onClick={() => { setAddingItemToCatId(null); setNewItemName('') }}
                                   className="p-1 text-slate-400 hover:text-slate-600"><X size={13} /></button>
                               </div>
                             )}
@@ -287,11 +287,11 @@ export default function PackingTemplateManager() {
                         onKeyDown={e => { if (e.key === 'Enter') handleAddCategory(); if (e.key === 'Escape') { setAddingCategory(false); setNewCatName('') } }}
                         placeholder={t('admin.packingTemplates.categoryName')}
                         className="flex-1 px-3 py-2 border border-slate-200 rounded-lg text-sm" />
-                      <button onClick={handleAddCategory} className={`${btnIcon} text-slate-600 hover:text-slate-900`}><Check size={15} /></button>
-                      <button onClick={() => { setAddingCategory(false); setNewCatName('') }} className={`${btnIcon} text-slate-400`}><X size={15} /></button>
+                      <button type="button" onClick={handleAddCategory} className={`${btnIcon} text-slate-600 hover:text-slate-900`}><Check size={15} /></button>
+                      <button type="button" onClick={() => { setAddingCategory(false); setNewCatName('') }} className={`${btnIcon} text-slate-400`}><X size={15} /></button>
                     </div>
                   ) : (
-                    <button onClick={() => setAddingCategory(true)}
+                    <button type="button" onClick={() => setAddingCategory(true)}
                       className="flex items-center gap-2 px-3 py-2.5 w-full text-sm text-slate-400 hover:text-slate-600 border border-dashed border-slate-200 rounded-lg hover:border-slate-400 transition-colors">
                       <FolderPlus size={14} /> {t('admin.packingTemplates.addCategory')}
                     </button>
diff --git a/client/src/components/Admin/PermissionsPanel.tsx b/client/src/components/Admin/PermissionsPanel.tsx
index acab4f0c6..6b2b149b7 100644
--- a/client/src/components/Admin/PermissionsPanel.tsx
+++ b/client/src/components/Admin/PermissionsPanel.tsx
@@ -104,7 +104,7 @@ export default function PermissionsPanel(): React.ReactElement {
             <p className="text-xs text-slate-400 mt-0.5">{t('perm.subtitle')}</p>
           </div>
           <div className="flex items-center gap-2">
-            <button
+            <button type="button"
               onClick={handleReset}
               disabled={saving}
               title={t('perm.resetDefaults')}
@@ -114,7 +114,7 @@ export default function PermissionsPanel(): React.ReactElement {
               <RotateCcw className="w-3.5 h-3.5" />
               <span className="hidden sm:inline">{t('perm.resetDefaults')}</span>
             </button>
-            <button
+            <button type="button"
               onClick={handleSave}
               disabled={saving || !dirty}
               className="flex items-center gap-1.5 px-3 py-1.5 text-sm bg-slate-900 text-white rounded-lg hover:bg-slate-700 disabled:bg-slate-400 transition-colors"
diff --git a/client/src/components/Admin/storage/AdminStoragePanel.tsx b/client/src/components/Admin/storage/AdminStoragePanel.tsx
index d22abab2d..954ef6a2c 100644
--- a/client/src/components/Admin/storage/AdminStoragePanel.tsx
+++ b/client/src/components/Admin/storage/AdminStoragePanel.tsx
@@ -338,7 +338,7 @@ export default function AdminStoragePanel(): React.ReactElement {
             ? t('storage.usage.computed', { age: relativeTime(state.usage.computedAt, locale) })
             : t('storage.usage.never')}
           {' '}
-          <button className="text-xs underline text-content-secondary" style={LINK_BUTTON_STYLE} onClick={handleRefreshStats}>
+          <button type="button" className="text-xs underline text-content-secondary" style={LINK_BUTTON_STYLE} onClick={handleRefreshStats}>
             {state.usage ? t('storage.usage.refresh') : t('storage.usage.compute')}
           </button>
         </p>
@@ -364,7 +364,7 @@ export default function AdminStoragePanel(): React.ReactElement {
                     {t(`storage.source.${row.source}`)}
                   </span>
                   <span className="flex-1" />
-                  <button
+                  <button type="button"
                     className="text-xs underline text-content-secondary"
                     style={LINK_BUTTON_STYLE}
                     onClick={() =>
@@ -376,12 +376,12 @@ export default function AdminStoragePanel(): React.ReactElement {
                     {t('storage.actions.test')}
                   </button>
                   {row.source !== 'env' && (
-                    <button className="text-xs underline text-content-secondary" style={LINK_BUTTON_STYLE} onClick={() => startEdit(row)}>
+                    <button type="button" className="text-xs underline text-content-secondary" style={LINK_BUTTON_STYLE} onClick={() => startEdit(row)}>
                       {t('storage.actions.edit')}
                     </button>
                   )}
                   {row.source === 'settings' && (
-                    <button className="text-xs underline text-content-secondary" style={LINK_BUTTON_STYLE} onClick={() => setConfirmRemove({ name: row.name, degenerate: false })}>
+                    <button type="button" className="text-xs underline text-content-secondary" style={LINK_BUTTON_STYLE} onClick={() => setConfirmRemove({ name: row.name, degenerate: false })}>
                       {t('storage.actions.remove')}
                     </button>
                   )}
@@ -433,7 +433,7 @@ export default function AdminStoragePanel(): React.ReactElement {
                             failed: String(backfill.failed),
                           })}
                         </p>
-                        <button
+                        <button type="button"
                           className="text-xs underline text-content-secondary mt-1"
                           style={LINK_BUTTON_STYLE}
                           onClick={() => handleCancelBackfill(row)}
@@ -464,7 +464,7 @@ export default function AdminStoragePanel(): React.ReactElement {
                           </p>
                         )}
                         {syncPrompt !== row.name && (
-                          <button
+                          <button type="button"
                             className="text-xs underline text-content-secondary"
                             style={LINK_BUTTON_STYLE}
                             onClick={() => handleStartBackfill(row)}
@@ -480,14 +480,14 @@ export default function AdminStoragePanel(): React.ReactElement {
                   <div className="mt-2 rounded-lg border p-2 border-edge-secondary">
                     <p className="text-xs text-content">{t('storage.sync.prompt')}</p>
                     <div className="flex items-center gap-3 mt-1">
-                      <button
+                      <button type="button"
                         className="text-xs underline text-content-secondary"
                         style={LINK_BUTTON_STYLE}
                         onClick={() => handleStartBackfill(row)}
                       >
                         {t('storage.sync.now')}
                       </button>
-                      <button
+                      <button type="button"
                         className="text-xs underline text-content-secondary"
                         style={LINK_BUTTON_STYLE}
                         onClick={() => setSyncPrompt(null)}
@@ -512,10 +512,10 @@ export default function AdminStoragePanel(): React.ReactElement {
                     {t('storage.type.mirror')}
                   </span>
                   <span className="flex-1" />
-                  <button className="text-xs underline text-content-secondary" style={LINK_BUTTON_STYLE} onClick={() => admin.test(backend)}>
+                  <button type="button" className="text-xs underline text-content-secondary" style={LINK_BUTTON_STYLE} onClick={() => admin.test(backend)}>
                     {t('storage.actions.test')}
                   </button>
-                  <button className="text-xs underline text-content-secondary" style={LINK_BUTTON_STYLE} onClick={() => setConfirmRemove({ name: backend.name, degenerate: true })}>
+                  <button type="button" className="text-xs underline text-content-secondary" style={LINK_BUTTON_STYLE} onClick={() => setConfirmRemove({ name: backend.name, degenerate: true })}>
                     {t('storage.actions.remove')}
                   </button>
                 </div>
@@ -552,7 +552,7 @@ export default function AdminStoragePanel(): React.ReactElement {
                         total: String(m.total),
                       })}
                     </p>
-                    <button
+                    <button type="button"
                       className="text-xs underline text-content-secondary mt-1"
                       style={LINK_BUTTON_STYLE}
                       onClick={() => void handleCancelMigration(m)}
@@ -601,7 +601,7 @@ export default function AdminStoragePanel(): React.ReactElement {
             onCancel={() => setEditing(null)}
           />
         ) : (
-          <button
+          <button type="button"
             onClick={() =>
               setEditing({
                 initial: null,
@@ -675,7 +675,7 @@ export default function AdminStoragePanel(): React.ReactElement {
       </Section>
 
       <div className="flex items-center gap-3">
-        <button
+        <button type="button"
           onClick={save}
           disabled={!admin.dirty || admin.saving}
           style={{
@@ -715,21 +715,21 @@ export default function AdminStoragePanel(): React.ReactElement {
             </p>
           ))}
           <div className="flex items-center gap-3 mt-2">
-            <button
+            <button type="button"
               className="text-xs underline text-content-secondary"
               style={LINK_BUTTON_STYLE}
               onClick={() => void moveAndSave()}
             >
               {t('storage.migrate.move')}
             </button>
-            <button
+            <button type="button"
               className="text-xs underline text-content-secondary"
               style={LINK_BUTTON_STYLE}
               onClick={() => void routeOnlySave()}
             >
               {t('storage.migrate.routeOnly')}
             </button>
-            <button
+            <button type="button"
               className="text-xs underline text-content-secondary"
               style={LINK_BUTTON_STYLE}
               onClick={() => setMigratePromptOpen(false)}
@@ -746,7 +746,7 @@ export default function AdminStoragePanel(): React.ReactElement {
               past; "save again" can never clear it, so the banner offers the
               one action that can — see useStorageAdmin.discardDraft. */}
           {admin.saveConflict && (
-            <button
+            <button type="button"
               className="text-xs underline text-content-secondary mt-1"
               style={LINK_BUTTON_STYLE}
               onClick={() => void admin.discardDraft()}
diff --git a/client/src/components/Admin/storage/BackendForm.tsx b/client/src/components/Admin/storage/BackendForm.tsx
index c2293798c..1731a1623 100644
--- a/client/src/components/Admin/storage/BackendForm.tsx
+++ b/client/src/components/Admin/storage/BackendForm.tsx
@@ -236,7 +236,7 @@ export default function BackendForm({
       )}
 
       <div className="flex items-center gap-3">
-        <button
+        <button type="button"
           onClick={apply}
           disabled={!canApply}
           style={{
@@ -248,7 +248,7 @@ export default function BackendForm({
         >
           {t('storage.form.apply')}
         </button>
-        <button
+        <button type="button"
           onClick={onCancel}
           style={{
             padding: '8px 20px', borderRadius: 10, cursor: 'pointer', fontFamily: 'inherit',
diff --git a/client/src/components/BackgroundTasks/BackgroundTasksWidget.tsx b/client/src/components/BackgroundTasks/BackgroundTasksWidget.tsx
index 19c34b2a1..55ec57249 100644
--- a/client/src/components/BackgroundTasks/BackgroundTasksWidget.tsx
+++ b/client/src/components/BackgroundTasks/BackgroundTasksWidget.tsx
@@ -163,7 +163,7 @@ export default function BackgroundTasksWidget() {
                 <div style={{ fontSize: 'calc(11px * var(--fs-scale-caption, 1))', color: 'var(--text-faint)', marginTop: 1 }}>{t('reservations.import.parsing')}</div>
               ) : task.items.length > 0 ? (
                 <div>
-                  <button
+                  <button type="button"
                     onClick={() => review(task)}
                     className="bg-accent text-accent-text"
                     style={{ marginTop: 4, border: 'none', borderRadius: 8, padding: '4px 12px', fontSize: 'calc(11.5px * var(--fs-scale-caption, 1))', fontWeight: 600, cursor: 'pointer', fontFamily: 'inherit' }}
@@ -192,7 +192,7 @@ export default function BackgroundTasksWidget() {
                     )}
                   </div>
                   {aiParsing && task.mode !== 'force-ai' && task.sourceFiles && task.sourceFiles.length > 0 && (
-                    <button
+                    <button type="button"
                       onClick={() => retryWithAi(task)}
                       disabled={retrying === task.id}
                       className="bg-surface-tertiary text-content"
@@ -211,7 +211,7 @@ export default function BackgroundTasksWidget() {
           </div>
 
           {task.status !== 'running' && (
-            <button
+            <button type="button"
               onClick={() => dismiss(task.id)}
               className="bg-transparent text-content-faint"
               style={{ flexShrink: 0, border: 'none', cursor: 'pointer', padding: 2, borderRadius: 6, display: 'flex', alignItems: 'center' }}
diff --git a/client/src/components/Budget/BudgetPanel.helpers.ts b/client/src/components/Budget/BudgetPanel.helpers.ts
index 987b4a18d..9e183eda7 100644
--- a/client/src/components/Budget/BudgetPanel.helpers.ts
+++ b/client/src/components/Budget/BudgetPanel.helpers.ts
@@ -48,7 +48,7 @@ export function hexLighten(hex: string, amount: number): string {
   const m = hex.replace('#', '').match(/.{2}/g)
   if (!m || m.length !== 3) return hex
   const mix = (c: number) => Math.min(255, Math.round(c + (255 - c) * amount))
-  const [r, g, b] = m.map(x => parseInt(x, 16))
+  const [r, g, b] = m.map(x => Number.parseInt(x, 16))
   return `#${[mix(r), mix(g), mix(b)].map(v => v.toString(16).padStart(2, '0')).join('')}`
 }
 
diff --git a/client/src/components/Budget/BudgetPanel.tsx b/client/src/components/Budget/BudgetPanel.tsx
index 8876ad4eb..3fddf4e16 100644
--- a/client/src/components/Budget/BudgetPanel.tsx
+++ b/client/src/components/Budget/BudgetPanel.tsx
@@ -46,7 +46,7 @@ export default function BudgetPanel({ tripId, tripMembers = [] }: BudgetPanelPro
               onKeyDown={e => e.key === 'Enter' && handleAddCategory()}
               placeholder={t('budget.emptyPlaceholder')}
               style={{ flex: 1, padding: '9px 14px', borderRadius: 10, border: '1px solid var(--border-primary)', fontSize: 'calc(13px * var(--fs-scale-body, 1))', fontFamily: 'inherit', outline: 'none', background: 'var(--bg-input)', color: 'var(--text-primary)', minWidth: 0 }} />
-            <button onClick={handleAddCategory} disabled={!newCategoryName.trim()}
+            <button type="button" onClick={handleAddCategory} disabled={!newCategoryName.trim()}
               style={{ background: 'var(--accent)', color: 'var(--accent-text)', border: 'none', borderRadius: 10, padding: '0 12px', cursor: 'pointer', display: 'flex', alignItems: 'center', opacity: newCategoryName.trim() ? 1 : 0.5, flexShrink: 0 }}>
               <Plus size={16} />
             </button>
@@ -87,7 +87,7 @@ export default function BudgetPanel({ tripId, tripMembers = [] }: BudgetPanelPro
                   placeholder={t('budget.categoryName')}
                   style={{ flex: 1, minWidth: 0, border: '1px solid var(--border-primary)', borderRadius: 10, padding: '9px 14px', fontSize: 'calc(13px * var(--fs-scale-body, 1))', outline: 'none', fontFamily: 'inherit', background: 'var(--bg-card)', color: 'var(--text-primary)' }}
                 />
-                <button onClick={handleAddCategory} disabled={!newCategoryName.trim()}
+                <button type="button" onClick={handleAddCategory} disabled={!newCategoryName.trim()}
                   title={t('budget.addCategory')}
                   style={{
                     appearance: 'none', border: 'none', cursor: newCategoryName.trim() ? 'pointer' : 'default', fontFamily: 'inherit',
@@ -101,7 +101,7 @@ export default function BudgetPanel({ tripId, tripMembers = [] }: BudgetPanelPro
                 </button>
               </div>
             )}
-            <button onClick={handleExportCsv} title={t('budget.exportCsv')}
+            <button type="button" onClick={handleExportCsv} title={t('budget.exportCsv')}
               style={{
                 appearance: 'none', border: 'none', cursor: 'pointer', fontFamily: 'inherit',
                 display: 'inline-flex', alignItems: 'center', gap: 6,
diff --git a/client/src/components/Budget/BudgetPanelAddItemRow.tsx b/client/src/components/Budget/BudgetPanelAddItemRow.tsx
index 5f9deb4fa..f19e438d2 100644
--- a/client/src/components/Budget/BudgetPanelAddItemRow.tsx
+++ b/client/src/components/Budget/BudgetPanelAddItemRow.tsx
@@ -19,7 +19,7 @@ export default function AddItemRow({ onAdd, t }: AddItemRowProps) {
 
   const handleAdd = () => {
     if (!name.trim()) return
-    onAdd({ name: name.trim(), total_price: parseFloat(String(price).replace(',', '.')) || 0, persons: parseInt(persons) || null, days: parseInt(days) || null, note: note.trim() || null, expense_date: expenseDate || null })
+    onAdd({ name: name.trim(), total_price: Number.parseFloat(String(price).replace(',', '.')) || 0, persons: Number.parseInt(persons) || null, days: Number.parseInt(days) || null, note: note.trim() || null, expense_date: expenseDate || null })
     setName(''); setPrice(''); setPersons(''); setDays(''); setNote(''); setExpenseDate('')
     setTimeout(() => nameRef.current?.focus(), 50)
   }
@@ -57,7 +57,7 @@ export default function AddItemRow({ onAdd, t }: AddItemRowProps) {
         <input value={note} onChange={e => setNote(e.target.value)} onKeyDown={e => e.key === 'Enter' && handleAdd()} placeholder={t('budget.table.note')} style={inp} />
       </td>
       <td style={{ padding: '4px 6px', textAlign: 'center' }}>
-        <button onClick={handleAdd} disabled={!name.trim()} title={t('reservations.add')}
+        <button type="button" onClick={handleAdd} disabled={!name.trim()} title={t('reservations.add')}
           style={{ background: name.trim() ? 'var(--text-primary)' : 'var(--border-primary)', border: 'none', borderRadius: 4, color: 'var(--bg-primary)',
             cursor: name.trim() ? 'pointer' : 'default', padding: '4px 8px', display: 'inline-flex', alignItems: 'center' }}>
           <Plus size={14} />
diff --git a/client/src/components/Budget/BudgetPanelCategoryTable.tsx b/client/src/components/Budget/BudgetPanelCategoryTable.tsx
index cd172325d..e68346e48 100644
--- a/client/src/components/Budget/BudgetPanelCategoryTable.tsx
+++ b/client/src/components/Budget/BudgetPanelCategoryTable.tsx
@@ -111,7 +111,7 @@ export default function BudgetCategoryTable({ cat, grouped, categoryColor, canEd
                       <>
                         <span style={{ fontWeight: 600, fontSize: 'calc(13px * var(--fs-scale-body, 1))' }}>{cat}</span>
                         {canEdit && (
-                          <button onClick={() => setEditingCat({ name: cat, value: cat })}
+                          <button type="button" onClick={() => setEditingCat({ name: cat, value: cat })}
                             style={{ background: 'none', border: 'none', cursor: 'pointer', color: 'rgba(255,255,255,0.4)', display: 'flex', padding: 1 }}
                             onMouseEnter={e => e.currentTarget.style.color = '#fff'} onMouseLeave={e => e.currentTarget.style.color = 'rgba(255,255,255,0.4)'}>
                             <Pencil size={10} />
@@ -123,7 +123,7 @@ export default function BudgetCategoryTable({ cat, grouped, categoryColor, canEd
                   <div style={{ display: 'flex', alignItems: 'center', gap: 10 }}>
                     <span style={{ fontSize: 'calc(13px * var(--fs-scale-body, 1))', fontWeight: 500, opacity: 0.9 }}>{fmt(subtotal, currency)}</span>
                     {canEdit && (
-                      <button onClick={() => handleDeleteCategory(cat)} title={t('budget.deleteCategory')}
+                      <button type="button" onClick={() => handleDeleteCategory(cat)} title={t('budget.deleteCategory')}
                         style={{ background: 'rgba(255,255,255,0.1)', border: 'none', borderRadius: 4, color: '#fff', cursor: 'pointer', padding: '3px 6px', display: 'flex', alignItems: 'center', opacity: 0.6 }}
                         onMouseEnter={e => e.currentTarget.style.opacity = '1'} onMouseLeave={e => e.currentTarget.style.opacity = '0.6'}>
                         <Trash2 size={13} />
@@ -225,11 +225,11 @@ export default function BudgetCategoryTable({ cat, grouped, categoryColor, canEd
                                   readOnly={!canEdit}
                                 />
                               ) : (
-                                <InlineEditCell value={item.persons} type="number" decimals={0} onSave={v => handleUpdateField(item.id, 'persons', v != null ? parseInt(v as string) || null : null)} style={{ textAlign: 'center' }} placeholder="-" locale={locale} editTooltip={t('budget.editTooltip')} readOnly={!canEdit} />
+                                <InlineEditCell value={item.persons} type="number" decimals={0} onSave={v => handleUpdateField(item.id, 'persons', v != null ? Number.parseInt(v as string) || null : null)} style={{ textAlign: 'center' }} placeholder="-" locale={locale} editTooltip={t('budget.editTooltip')} readOnly={!canEdit} />
                               )}
                             </td>
                             <td className="hidden sm:table-cell" style={{ ...td, textAlign: 'center' }}>
-                              <InlineEditCell value={item.days} type="number" decimals={0} onSave={v => handleUpdateField(item.id, 'days', v != null ? parseInt(v as string) || null : null)} style={{ textAlign: 'center' }} placeholder="-" locale={locale} editTooltip={t('budget.editTooltip')} readOnly={!canEdit} />
+                              <InlineEditCell value={item.days} type="number" decimals={0} onSave={v => handleUpdateField(item.id, 'days', v != null ? Number.parseInt(v as string) || null : null)} style={{ textAlign: 'center' }} placeholder="-" locale={locale} editTooltip={t('budget.editTooltip')} readOnly={!canEdit} />
                             </td>
                             <td className="hidden md:table-cell" style={{ ...td, textAlign: 'center', color: pp != null ? 'var(--text-secondary)' : 'var(--text-faint)' }}>{pp != null ? fmt(pp, currency) : '-'}</td>
                             <td className="hidden md:table-cell" style={{ ...td, textAlign: 'center', color: pd != null ? 'var(--text-secondary)' : 'var(--text-faint)' }}>{pd != null ? fmt(pd, currency) : '-'}</td>
@@ -246,7 +246,7 @@ export default function BudgetCategoryTable({ cat, grouped, categoryColor, canEd
                             <td className="hidden sm:table-cell" style={td}><InlineEditCell value={item.note} onSave={v => handleUpdateField(item.id, 'note', v)} placeholder={t('budget.table.note')} locale={locale} editTooltip={t('budget.editTooltip')} readOnly={!canEdit} /></td>
                             <td style={{ ...td, textAlign: 'center' }}>
                               {canEdit && (
-                              <button onClick={() => handleDeleteItem(item.id)} title={t('common.delete')}
+                              <button type="button" onClick={() => handleDeleteItem(item.id)} title={t('common.delete')}
                                 style={{ background: 'none', border: 'none', cursor: 'pointer', padding: 4, color: 'var(--text-faint)', borderRadius: 4, display: 'inline-flex', transition: 'color 0.15s' }}
                                 onMouseEnter={e => e.currentTarget.style.color = '#ef4444'} onMouseLeave={e => e.currentTarget.style.color = '#d1d5db'}>
                                 <Trash2 size={14} />
diff --git a/client/src/components/Budget/BudgetPanelInlineEditCell.tsx b/client/src/components/Budget/BudgetPanelInlineEditCell.tsx
index 159bd500d..a5c6bcd9e 100644
--- a/client/src/components/Budget/BudgetPanelInlineEditCell.tsx
+++ b/client/src/components/Budget/BudgetPanelInlineEditCell.tsx
@@ -23,7 +23,7 @@ export default function InlineEditCell({ value, onSave, type = 'text', style = {
   const save = () => {
     setEditing(false)
     let v: string | number | null = editValue
-    if (type === 'number') { const p = parseFloat(String(editValue).replace(',', '.')); v = isNaN(p) ? null : p }
+    if (type === 'number') { const p = Number.parseFloat(String(editValue).replace(',', '.')); v = isNaN(p) ? null : p }
     if (v !== value) onSave(v)
   }
 
diff --git a/client/src/components/Budget/BudgetPanelMemberChips.tsx b/client/src/components/Budget/BudgetPanelMemberChips.tsx
index 376464f12..3cc256dec 100644
--- a/client/src/components/Budget/BudgetPanelMemberChips.tsx
+++ b/client/src/components/Budget/BudgetPanelMemberChips.tsx
@@ -131,7 +131,7 @@ export default function BudgetMemberChips({ members = [], tripMembers = [], onSe
         />
       ))}
       {!readOnly && (
-        <button ref={btnRef} onClick={openDropdown}
+        <button type="button" ref={btnRef} onClick={openDropdown}
           style={{
             width: btnSize, height: btnSize, borderRadius: '50%', border: '1.5px dashed var(--border-primary)',
             background: 'none', cursor: 'pointer', display: 'flex', alignItems: 'center', justifyContent: 'center',
@@ -149,7 +149,7 @@ export default function BudgetMemberChips({ members = [], tripMembers = [], onSe
           {tripMembers.map(tm => {
             const isActive = memberIds.includes(tm.id)
             return (
-              <button key={tm.id} onClick={() => toggleMember(tm.id)} style={{
+              <button type="button" key={tm.id} onClick={() => toggleMember(tm.id)} style={{
                 display: 'flex', alignItems: 'center', gap: 6, width: '100%', padding: '5px 8px',
                 borderRadius: 6, border: 'none', background: isActive ? 'var(--bg-hover)' : 'none', cursor: 'pointer',
                 fontFamily: 'inherit', fontSize: 'calc(11px * var(--fs-scale-caption, 1))', color: 'var(--text-primary)', textAlign: 'left',
diff --git a/client/src/components/Budget/BudgetPanelSummary.tsx b/client/src/components/Budget/BudgetPanelSummary.tsx
index 70abfae18..6149e813a 100644
--- a/client/src/components/Budget/BudgetPanelSummary.tsx
+++ b/client/src/components/Budget/BudgetPanelSummary.tsx
@@ -75,7 +75,7 @@ export default function BudgetSummary({ theme, currency, locale, grandTotal, has
             {/* Settlement dropdown inside the total card */}
             {hasMultipleMembers && settlement && settlement.flows.length > 0 && (
               <div style={{ marginTop: 16, borderTop: `1px solid ${theme.divider}`, paddingTop: 12 }}>
-                <button onClick={() => setSettlementOpen(v => !v)} style={{
+                <button type="button" onClick={() => setSettlementOpen(v => !v)} style={{
                   display: 'flex', alignItems: 'center', gap: 6, width: '100%',
                   background: 'none', border: 'none', cursor: 'pointer', padding: 0, fontFamily: 'inherit',
                   color: theme.sub, fontSize: 'calc(11px * var(--fs-scale-caption, 1))', fontWeight: 600, letterSpacing: 0.5,
diff --git a/client/src/components/Budget/CostsPanel.helpers.ts b/client/src/components/Budget/CostsPanel.helpers.ts
index 8bc566144..6226d289c 100644
--- a/client/src/components/Budget/CostsPanel.helpers.ts
+++ b/client/src/components/Budget/CostsPanel.helpers.ts
@@ -22,7 +22,7 @@ export function splitCents(amount: number, n: number): number[] {
 
 /** Sum the amounts of the selected payers. */
 export function payerSum(amounts: Record<number, string>, ids: Set<number>): number {
-  return [...ids].reduce((a, id) => a + (parseFloat(amounts[id]) || 0), 0)
+  return [...ids].reduce((a, id) => a + (Number.parseFloat(amounts[id]) || 0), 0)
 }
 
 /** True when the payer amounts add up to the expense total, to the cent. */
@@ -45,7 +45,7 @@ export function rebalancePayers(
   if (free.length === 0) return amounts
   const pinnedSum = all
     .filter(id => pinned.has(id))
-    .reduce((a, id) => a + (parseFloat(amounts[id]) || 0), 0)
+    .reduce((a, id) => a + (Number.parseFloat(amounts[id]) || 0), 0)
   const shares = splitCents(total - pinnedSum, free.length)
   const next = { ...amounts }
   free.forEach((id, i) => { next[id] = shares[i] ? shares[i].toFixed(2) : '' })
@@ -153,7 +153,7 @@ export function calculateTicketShares(items: TicketItem[]): { shares: Record<num
   const everyone = [...new Set(items.flatMap(i => [...i.participants]))].sort((a, b) => a - b)
 
   for (const item of items) {
-    const priceNum = parseFloat(item.price) || 0
+    const priceNum = Number.parseFloat(item.price) || 0
     const priceCents = Math.round(priceNum * 100)
     totalCents += priceCents
 
diff --git a/client/src/components/Budget/CostsPanel.tsx b/client/src/components/Budget/CostsPanel.tsx
index d1badfa7a..302a1856d 100644
--- a/client/src/components/Budget/CostsPanel.tsx
+++ b/client/src/components/Budget/CostsPanel.tsx
@@ -348,12 +348,12 @@ export default function CostsPanel({ tripId, tripMembers = [] }: CostsPanelProps
         </div>
         {canEdit && (
           <div style={{ display: 'flex', gap: 10 }}>
-            <button onClick={settleAll} disabled={!(settlement?.flows || []).length}
+            <button type="button" onClick={settleAll} disabled={!(settlement?.flows || []).length}
               className="bg-surface-card border border-edge text-content disabled:opacity-40"
               style={{ display: 'inline-flex', alignItems: 'center', gap: 7, padding: '10px 16px', borderRadius: 12, fontSize: 'calc(14px * var(--fs-scale-body, 1))', fontWeight: 500, cursor: 'pointer', fontFamily: 'inherit' }}>
               <Check size={16} /> {t('costs.settleUp')}
             </button>
-            <button onClick={() => { setEditing(null); setModalOpen(true) }}
+            <button type="button" onClick={() => { setEditing(null); setModalOpen(true) }}
               className="bg-[var(--text-primary)] text-[var(--bg-primary)]"
               style={{ display: 'inline-flex', alignItems: 'center', gap: 7, padding: '10px 18px', borderRadius: 12, fontSize: 'calc(14px * var(--fs-scale-body, 1))', fontWeight: 600, border: 0, cursor: 'pointer', fontFamily: 'inherit' }}>
               <Plus size={16} /> {t('costs.addExpense')}
@@ -401,14 +401,14 @@ export default function CostsPanel({ tripId, tripMembers = [] }: CostsPanelProps
               {filterControls}
               <div className="bg-surface-secondary" style={{ display: 'flex', borderRadius: 9, padding: 3 }}>
                 {(['all', 'mine', 'owed'] as const).map(f => (
-                  <button key={f} onClick={() => setFilter(f)}
+                  <button type="button" key={f} onClick={() => setFilter(f)}
                     className={filter === f ? 'bg-surface-card text-content' : 'text-content-muted'}
                     style={{ padding: '6px 11px', fontSize: 'calc(12px * var(--fs-scale-body, 1))', borderRadius: 7, fontWeight: 500, border: 0, cursor: 'pointer', fontFamily: 'inherit' }}>
                     {t('costs.filter.' + f)}
                   </button>
                 ))}
               </div>
-              <button onClick={handleExportCsv} title={t('budget.exportCsv')} disabled={!budgetItems.length}
+              <button type="button" onClick={handleExportCsv} title={t('budget.exportCsv')} disabled={!budgetItems.length}
                 className="bg-surface-input border border-edge text-content-muted disabled:opacity-40"
                 style={{ display: 'inline-flex', alignItems: 'center', justifyContent: 'center', width: 34, height: 34, borderRadius: 10, cursor: 'pointer', fontFamily: 'inherit', flexShrink: 0 }}>
                 <Download size={15} />
@@ -451,7 +451,7 @@ export default function CostsPanel({ tripId, tripMembers = [] }: CostsPanelProps
             <div style={{ display: 'flex', alignItems: 'center', justifyContent: 'space-between', marginBottom: 14 }}>
               <div className={labelCls}>{t('costs.settleUp')} · <span className="text-content">{(settlement?.flows || []).length}</span></div>
               {canEdit && (
-                <button onClick={() => setAddingPayment(true)}
+                <button type="button" onClick={() => setAddingPayment(true)}
                   className="text-content-muted bg-surface-secondary border border-edge"
                   style={{ display: 'inline-flex', alignItems: 'center', gap: 5, padding: '5px 9px', borderRadius: 8, fontSize: 'calc(11.5px * var(--fs-scale-caption, 1))', fontWeight: 600, cursor: 'pointer', fontFamily: 'inherit' }}>
                   <Plus size={13} /> {t('costs.addPayment')}
@@ -560,7 +560,7 @@ export default function CostsPanel({ tripId, tripMembers = [] }: CostsPanelProps
             </div>
             <div style={{ display: 'flex', alignItems: 'center', gap: 8, flexShrink: 0 }}>
               <span className="text-content" style={{ fontSize: 'calc(14px * var(--fs-scale-body, 1))', fontWeight: 700 }}>{fmt(f.amount)}</span>
-              {canEdit && <button onClick={() => settleFlow(f.from.user_id, f.to.user_id, f.amount)} className="bg-[var(--text-primary)] text-[var(--bg-primary)]" style={{ padding: '7px 12px', borderRadius: 9, fontSize: 'calc(12px * var(--fs-scale-body, 1))', fontWeight: 600, border: 0, cursor: 'pointer', fontFamily: 'inherit' }}>{t('costs.settle')}</button>}
+              {canEdit && <button type="button" onClick={() => settleFlow(f.from.user_id, f.to.user_id, f.amount)} className="bg-[var(--text-primary)] text-[var(--bg-primary)]" style={{ padding: '7px 12px', borderRadius: 9, fontSize: 'calc(12px * var(--fs-scale-body, 1))', fontWeight: 600, border: 0, cursor: 'pointer', fontFamily: 'inherit' }}>{t('costs.settle')}</button>}
             </div>
           </div>
         ))}
@@ -589,7 +589,7 @@ export default function CostsPanel({ tripId, tripMembers = [] }: CostsPanelProps
             <span>{t('costs.youPaid')} · <b style={{ color: '#fff', fontWeight: 600 }}>{fmt0(totals.myPaid)}</b></span>
           </div>
           {canEdit && (
-            <button onClick={() => { setEditing(null); setModalOpen(true) }} style={{ marginTop: 16, width: '100%', display: 'flex', alignItems: 'center', justifyContent: 'center', gap: 8, background: 'rgba(255,255,255,0.14)', border: '1px solid rgba(255,255,255,0.16)', color: '#fff', padding: 13, borderRadius: 14, fontSize: 'calc(14px * var(--fs-scale-body, 1))', fontWeight: 600, cursor: 'pointer', fontFamily: 'inherit' }}>
+            <button type="button" onClick={() => { setEditing(null); setModalOpen(true) }} style={{ marginTop: 16, width: '100%', display: 'flex', alignItems: 'center', justifyContent: 'center', gap: 8, background: 'rgba(255,255,255,0.14)', border: '1px solid rgba(255,255,255,0.16)', color: '#fff', padding: 13, borderRadius: 14, fontSize: 'calc(14px * var(--fs-scale-body, 1))', fontWeight: 600, cursor: 'pointer', fontFamily: 'inherit' }}>
               <Plus size={17} /> {t('costs.addExpense')}
             </button>
           )}
@@ -628,7 +628,7 @@ export default function CostsPanel({ tripId, tripMembers = [] }: CostsPanelProps
           <div style={{ display: 'flex', alignItems: 'center', justifyContent: 'space-between', marginBottom: 14, gap: 8 }}>
             <div className="text-content" style={{ fontSize: 'calc(19px * var(--fs-scale-subtitle, 1))', fontWeight: 700, letterSpacing: '-0.02em', display: 'flex', alignItems: 'baseline', gap: 8 }}>{t('costs.settleUp')} <span className="text-content-faint" style={{ fontSize: 'calc(12px * var(--fs-scale-body, 1))', fontWeight: 500 }}>{(settlement?.flows || []).length}</span></div>
             {canEdit && (
-              <button onClick={() => setAddingPayment(true)} className="text-content-muted bg-surface-card border border-edge" style={{ display: 'inline-flex', alignItems: 'center', gap: 5, padding: '6px 10px', borderRadius: 9, fontSize: 'calc(11.5px * var(--fs-scale-caption, 1))', fontWeight: 600, cursor: 'pointer', fontFamily: 'inherit' }}><Plus size={13} /> {t('costs.addPayment')}</button>
+              <button type="button" onClick={() => setAddingPayment(true)} className="text-content-muted bg-surface-card border border-edge" style={{ display: 'inline-flex', alignItems: 'center', gap: 5, padding: '6px 10px', borderRadius: 9, fontSize: 'calc(11.5px * var(--fs-scale-caption, 1))', fontWeight: 600, cursor: 'pointer', fontFamily: 'inherit' }}><Plus size={13} /> {t('costs.addPayment')}</button>
             )}
           </div>
           {SettleFlows()}
@@ -638,7 +638,7 @@ export default function CostsPanel({ tripId, tripMembers = [] }: CostsPanelProps
         <div style={{ display: 'flex', flexDirection: 'column', gap: 12 }}>
           <div style={{ display: 'flex', alignItems: 'center', justifyContent: 'space-between', gap: 8 }}>
             <div className="text-content" style={{ fontSize: 'calc(19px * var(--fs-scale-subtitle, 1))', fontWeight: 700, letterSpacing: '-0.02em' }}>{t('costs.expenses')}</div>
-            <button onClick={handleExportCsv} title={t('budget.exportCsv')} disabled={!budgetItems.length}
+            <button type="button" onClick={handleExportCsv} title={t('budget.exportCsv')} disabled={!budgetItems.length}
               className="bg-surface-card border border-edge text-content-muted disabled:opacity-40"
               style={{ display: 'inline-flex', alignItems: 'center', justifyContent: 'center', width: 34, height: 34, borderRadius: 10, cursor: 'pointer', fontFamily: 'inherit', flexShrink: 0 }}>
               <Download size={15} />
@@ -650,7 +650,7 @@ export default function CostsPanel({ tripId, tripMembers = [] }: CostsPanelProps
           </div>
           <div className="bg-surface-secondary" style={{ display: 'flex', borderRadius: 11, padding: 3, gap: 2 }}>
             {(['all', 'mine', 'owed'] as const).map(f => (
-              <button key={f} onClick={() => setFilter(f)} className={filter === f ? 'bg-surface-card text-content' : 'text-content-muted'} style={{ flex: 1, padding: '8px 6px', fontSize: 'calc(12.5px * var(--fs-scale-body, 1))', fontWeight: 500, borderRadius: 8, border: 0, cursor: 'pointer', fontFamily: 'inherit', whiteSpace: 'nowrap' }}>{t('costs.filter.' + f)}</button>
+              <button type="button" key={f} onClick={() => setFilter(f)} className={filter === f ? 'bg-surface-card text-content' : 'text-content-muted'} style={{ flex: 1, padding: '8px 6px', fontSize: 'calc(12.5px * var(--fs-scale-body, 1))', fontWeight: 500, borderRadius: 8, border: 0, cursor: 'pointer', fontFamily: 'inherit', whiteSpace: 'nowrap' }}>{t('costs.filter.' + f)}</button>
             ))}
           </div>
           <div style={{ display: 'flex', gap: 8 }}>
@@ -705,7 +705,7 @@ export default function CostsPanel({ tripId, tripMembers = [] }: CostsPanelProps
     }
     return (
       <div className="exp-actions bg-surface-card border border-edge" style={{ display: 'flex', flexDirection: 'column', justifyContent: 'center', gap: 3, flexShrink: 0, borderRadius: 999, padding: 5 }}>
-        <button title={t('common.edit')} onClick={onEdit} className="text-content-muted transition-colors" style={btn}><Pencil size={13} /></button>
+        <button type="button" title={t('common.edit')} onClick={onEdit} className="text-content-muted transition-colors" style={btn}><Pencil size={13} /></button>
         <button title={deleteLabel} onClick={onDelete} className="exp-action-danger transition-colors" style={{ ...btn, color: '#dc2626' }}><Trash2 size={13} /></button>
       </div>
     )
@@ -839,8 +839,8 @@ export default function CostsPanel({ tripId, tripMembers = [] }: CostsPanelProps
       </div>
       {canEdit && (
         <div className="exp-actions bg-surface-card border border-edge" style={{ display: 'flex', flexDirection: 'column', justifyContent: 'center', gap: 3, flexShrink: 0, borderRadius: 999, padding: 5 }}>
-          <button title={t('common.edit')} onClick={() => setEditingSettlement(s)} className="text-content-muted transition-colors" style={{ display: 'inline-flex', alignItems: 'center', justifyContent: 'center', width: 30, height: 30, borderRadius: 999, border: 0, cursor: 'pointer', padding: 0 }}><Pencil size={13} /></button>
-          <button title={t('costs.undo')} onClick={() => undoSettlement(s.id)} className="exp-action-danger transition-colors" style={{ display: 'inline-flex', alignItems: 'center', justifyContent: 'center', width: 30, height: 30, borderRadius: 999, border: 0, cursor: 'pointer', padding: 0, color: '#dc2626' }}><RotateCcw size={13} /></button>
+          <button type="button" title={t('common.edit')} onClick={() => setEditingSettlement(s)} className="text-content-muted transition-colors" style={{ display: 'inline-flex', alignItems: 'center', justifyContent: 'center', width: 30, height: 30, borderRadius: 999, border: 0, cursor: 'pointer', padding: 0 }}><Pencil size={13} /></button>
+          <button type="button" title={t('costs.undo')} onClick={() => undoSettlement(s.id)} className="exp-action-danger transition-colors" style={{ display: 'inline-flex', alignItems: 'center', justifyContent: 'center', width: 30, height: 30, borderRadius: 999, border: 0, cursor: 'pointer', padding: 0, color: '#dc2626' }}><RotateCcw size={13} /></button>
         </div>
       )}
       </div>
@@ -970,7 +970,7 @@ function SettlementModal({ tripId, people, me, editing, currency, onClose, onSav
   const [cur, setCur] = useState<string>((editing?.currency || currency).toUpperCase())
   const [saving, setSaving] = useState(false)
 
-  const amt = parseFloat(amount) || 0
+  const amt = Number.parseFloat(amount) || 0
   const valid = amt > 0 && fromId !== toId
   const opts = people.map(p => ({ value: String(p.id), label: p.id === me ? t('costs.you') : p.username }))
 
@@ -991,8 +991,8 @@ function SettlementModal({ tripId, people, me, editing, currency, onClose, onSav
     <Modal isOpen onClose={onClose} title={editing ? t('costs.editPayment') : t('costs.addPayment')} size="md"
       footer={
         <div style={{ display: 'flex', justifyContent: 'flex-end', gap: 8 }}>
-          <button onClick={onClose} className="text-content-muted border border-edge" style={{ padding: '8px 16px', borderRadius: 10, background: 'none', fontSize: 'calc(13px * var(--fs-scale-body, 1))', cursor: 'pointer', fontFamily: 'inherit' }}>{t('common.cancel')}</button>
-          <button onClick={save} disabled={!valid || saving} className="bg-[var(--text-primary)] text-[var(--bg-primary)]" style={{ padding: '8px 20px', borderRadius: 10, border: 0, fontSize: 'calc(13px * var(--fs-scale-body, 1))', fontWeight: 600, cursor: 'pointer', fontFamily: 'inherit', opacity: !valid || saving ? 0.5 : 1 }}>{editing ? t('common.save') : t('costs.addPayment')}</button>
+          <button type="button" onClick={onClose} className="text-content-muted border border-edge" style={{ padding: '8px 16px', borderRadius: 10, background: 'none', fontSize: 'calc(13px * var(--fs-scale-body, 1))', cursor: 'pointer', fontFamily: 'inherit' }}>{t('common.cancel')}</button>
+          <button type="button" onClick={save} disabled={!valid || saving} className="bg-[var(--text-primary)] text-[var(--bg-primary)]" style={{ padding: '8px 20px', borderRadius: 10, border: 0, fontSize: 'calc(13px * var(--fs-scale-body, 1))', fontWeight: 600, cursor: 'pointer', fontFamily: 'inherit', opacity: !valid || saving ? 0.5 : 1 }}>{editing ? t('common.save') : t('costs.addPayment')}</button>
         </div>
       }>
       <div style={{ display: 'flex', flexDirection: 'column', gap: 14 }}>
@@ -1116,8 +1116,8 @@ export function ExpenseModal({ tripId, base, people, me, editing, prefill, onClo
     return calculateTicketShares(ticketItems)
   }, [ticketItems])
 
-  const totalNum = isTicketMode ? ticketInfo.total : (parseFloat(total) || 0)
-  const splitSum = [...participants].reduce((sum, id) => sum + (parseFloat(customAmounts[id]) || 0), 0)
+  const totalNum = isTicketMode ? ticketInfo.total : (Number.parseFloat(total) || 0)
+  const splitSum = [...participants].reduce((sum, id) => sum + (Number.parseFloat(customAmounts[id]) || 0), 0)
   const customBalanced = Math.round(splitSum * 100) === Math.round(totalNum * 100)
   const each = participants.size > 0 ? totalNum / participants.size : 0
   const equalShares = useMemo(() => {
@@ -1130,13 +1130,13 @@ export function ExpenseModal({ tripId, base, people, me, editing, prefill, onClo
 
     const enteredSum = [...participants]
       .filter(id => customAmounts[id])
-      .reduce((sum, id) => sum + (parseFloat(customAmounts[id]) || 0), 0)
+      .reduce((sum, id) => sum + (Number.parseFloat(customAmounts[id]) || 0), 0)
     const remaining = Math.max(0, totalNum - enteredSum)
 
     return splitEqualShares(remaining, emptyParts.map(id => ({ user_id: id })), editing?.id || 0)
   }, [totalNum, participants, customAmounts, editing])
   
-  const ticketValid = ticketItems.length > 0 && ticketItems.every(item => item.name.trim().length > 0 && (parseFloat(item.price) || 0) > 0 && item.participants.size > 0)
+  const ticketValid = ticketItems.length > 0 && ticketItems.every(item => item.name.trim().length > 0 && (Number.parseFloat(item.price) || 0) > 0 && item.participants.size > 0)
   const payersOk = !multiPayer || (payerIds.size > 0 && payersBalanced(payerAmounts, payerIds, totalNum))
   const valid = name.trim().length > 0 && payersOk && (
     isTicketMode
@@ -1263,7 +1263,7 @@ export function ExpenseModal({ tripId, base, people, me, editing, prefill, onClo
     // dropping the payer would store the entry with a total of 0.
     const payerList = multiPayer
       ? [...payerIds]
-          .map(id => ({ user_id: id, amount: parseFloat(payerAmounts[id]) || 0 }))
+          .map(id => ({ user_id: id, amount: Number.parseFloat(payerAmounts[id]) || 0 }))
           .filter(p => p.amount > 0)
       : payerId > 0 ? [{ user_id: payerId, amount: totalNum }] : []
     // A receipt line can name somebody who is not ticked as a participant. Sending
@@ -1275,7 +1275,7 @@ export function ExpenseModal({ tripId, base, people, me, editing, prefill, onClo
     const memberList = memberIds.map(id => ({
       user_id: id,
       amount: splitMode === 'custom'
-        ? (parseFloat(customAmounts[id]) || 0)
+        ? (Number.parseFloat(customAmounts[id]) || 0)
         : splitMode === 'ticket'
         ? (ticketInfo.shares[id] || 0)
         : null
@@ -1315,8 +1315,8 @@ export function ExpenseModal({ tripId, base, people, me, editing, prefill, onClo
     <Modal isOpen onClose={onClose} title={editing ? t('costs.editExpense') : t('costs.addExpense')} size={isMobile ? '2xl' : '5xl'}
       footer={
         <div style={{ display: 'flex', justifyContent: 'flex-end', gap: 8 }}>
-          <button onClick={onClose} className="text-content-muted border border-edge" style={{ padding: '8px 16px', borderRadius: 10, background: 'none', fontSize: 'calc(13px * var(--fs-scale-body, 1))', cursor: 'pointer', fontFamily: 'inherit' }}>{t('common.cancel')}</button>
-          <button onClick={save} disabled={!valid || saving} className="bg-[var(--text-primary)] text-[var(--bg-primary)]" style={{ padding: '8px 20px', borderRadius: 10, border: 0, fontSize: 'calc(13px * var(--fs-scale-body, 1))', fontWeight: 600, cursor: 'pointer', fontFamily: 'inherit', opacity: !valid || saving ? 0.5 : 1 }}>{editing ? t('common.save') : t('costs.addExpense')}</button>
+          <button type="button" onClick={onClose} className="text-content-muted border border-edge" style={{ padding: '8px 16px', borderRadius: 10, background: 'none', fontSize: 'calc(13px * var(--fs-scale-body, 1))', cursor: 'pointer', fontFamily: 'inherit' }}>{t('common.cancel')}</button>
+          <button type="button" onClick={save} disabled={!valid || saving} className="bg-[var(--text-primary)] text-[var(--bg-primary)]" style={{ padding: '8px 20px', borderRadius: 10, border: 0, fontSize: 'calc(13px * var(--fs-scale-body, 1))', fontWeight: 600, cursor: 'pointer', fontFamily: 'inherit', opacity: !valid || saving ? 0.5 : 1 }}>{editing ? t('common.save') : t('costs.addExpense')}</button>
         </div>
       }>
       {/* Two columns on desktop: what the expense was on the left, how it is
@@ -1370,7 +1370,7 @@ export function ExpenseModal({ tripId, base, people, me, editing, prefill, onClo
             {COST_CATEGORY_LIST.map(c => {
               const Icon = c.Icon; const on = cat === c.key
               return (
-                <button key={c.key} onClick={() => setCat(c.key)}
+                <button type="button" key={c.key} onClick={() => setCat(c.key)}
                   className={on ? 'bg-surface-card text-content border' : 'bg-surface-secondary text-content-muted border border-edge'}
                   style={{ display: 'inline-flex', alignItems: 'center', gap: 6, padding: '6px 11px 6px 7px', borderRadius: 999, fontSize: 'calc(12.5px * var(--fs-scale-body, 1))', fontWeight: 500, cursor: 'pointer', fontFamily: 'inherit', borderColor: on ? 'var(--text-primary)' : undefined }}>
                   <span style={{ width: 20, height: 20, borderRadius: 6, display: 'grid', placeItems: 'center', background: c.color + '22', color: c.color }}><Icon size={12} /></span>
diff --git a/client/src/components/Collab/CollabChat.tsx b/client/src/components/Collab/CollabChat.tsx
index 7d5f0101c..597b8b86f 100644
--- a/client/src/components/Collab/CollabChat.tsx
+++ b/client/src/components/Collab/CollabChat.tsx
@@ -39,7 +39,7 @@ export default function CollabChat({ tripId, currentUser }: CollabChatProps) {
             <span style={{ overflow: 'hidden', textOverflow: 'ellipsis', whiteSpace: 'nowrap', flex: 1 }}>
               <strong>{replyTo.username}</strong>: {(replyTo.text || '').slice(0, 60)}
             </span>
-            <button onClick={() => setReplyTo(null)} style={{
+            <button type="button" onClick={() => setReplyTo(null)} style={{
               background: 'none', border: 'none', cursor: 'pointer', padding: 2, color: 'var(--text-faint)',
               display: 'flex', flexShrink: 0,
             }}>
@@ -51,7 +51,7 @@ export default function CollabChat({ tripId, currentUser }: CollabChatProps) {
         <div style={{ display: 'flex', alignItems: 'flex-end', gap: 6 }}>
           {/* Emoji button */}
           {canEdit && (
-            <button ref={emojiBtnRef} onClick={() => setShowEmoji(!showEmoji)} style={{
+            <button type="button" ref={emojiBtnRef} onClick={() => setShowEmoji(!showEmoji)} style={{
               width: 34, height: 34, borderRadius: '50%', border: 'none',
               background: showEmoji ? 'var(--bg-hover)' : 'transparent',
               color: 'var(--text-muted)', display: 'flex', alignItems: 'center', justifyContent: 'center',
@@ -80,7 +80,7 @@ export default function CollabChat({ tripId, currentUser }: CollabChatProps) {
 
           {/* Send */}
           {canEdit && (
-            <button onClick={handleSend} disabled={!text.trim() || sending} style={{
+            <button type="button" onClick={handleSend} disabled={!text.trim() || sending} style={{
               width: 34, height: 34, borderRadius: '50%', border: 'none',
               background: text.trim() ? '#007AFF' : 'var(--border-primary)',
               color: '#fff', display: 'flex', alignItems: 'center', justifyContent: 'center',
diff --git a/client/src/components/Collab/CollabChatEmojiPicker.tsx b/client/src/components/Collab/CollabChatEmojiPicker.tsx
index ec214351c..6561d1295 100644
--- a/client/src/components/Collab/CollabChatEmojiPicker.tsx
+++ b/client/src/components/Collab/CollabChatEmojiPicker.tsx
@@ -46,7 +46,7 @@ export function EmojiPicker({ onSelect, onClose, anchorRef, containerRef }: Emoj
       {/* Category tabs */}
       <div style={{ display: 'flex', borderBottom: '1px solid var(--border-faint)', padding: '6px 8px', gap: 2 }}>
         {Object.keys(EMOJI_CATEGORIES).map(c => (
-          <button key={c} onClick={() => setCat(c)} style={{
+          <button type="button" key={c} onClick={() => setCat(c)} style={{
             flex: 1, padding: '4px 0', borderRadius: 6, border: 'none', cursor: 'pointer',
             background: cat === c ? 'var(--bg-hover)' : 'transparent',
             color: 'var(--text-primary)', fontSize: 'calc(10px * var(--fs-scale-caption, 1))', fontWeight: 600, fontFamily: 'inherit',
@@ -58,7 +58,7 @@ export function EmojiPicker({ onSelect, onClose, anchorRef, containerRef }: Emoj
       {/* Emoji grid */}
       <div style={{ display: 'grid', gridTemplateColumns: 'repeat(10, 1fr)', gap: 2, padding: 8 }}>
         {EMOJI_CATEGORIES[cat].map((emoji, i) => (
-          <button key={i} onClick={() => onSelect(emoji)} style={{
+          <button type="button" key={i} onClick={() => onSelect(emoji)} style={{
             width: 28, height: 28, display: 'flex', alignItems: 'center', justifyContent: 'center',
             background: 'none', border: 'none', cursor: 'pointer', borderRadius: 6,
             padding: 2, transition: 'transform 0.1s',
diff --git a/client/src/components/Collab/CollabChatMessages.tsx b/client/src/components/Collab/CollabChatMessages.tsx
index 9427bee4c..6f94bdfcd 100644
--- a/client/src/components/Collab/CollabChatMessages.tsx
+++ b/client/src/components/Collab/CollabChatMessages.tsx
@@ -24,7 +24,7 @@ export function ChatMessages(props: any) {
         }}>
           {hasMore && (
             <div style={{ display: 'flex', justifyContent: 'center', padding: '4px 0 10px' }}>
-              <button onClick={handleLoadMore} disabled={loadingMore} style={{
+              <button type="button" onClick={handleLoadMore} disabled={loadingMore} style={{
                 display: 'inline-flex', alignItems: 'center', gap: 4, fontSize: 'calc(11px * var(--fs-scale-caption, 1))', fontWeight: 600,
                 color: 'var(--text-muted)', background: 'var(--bg-secondary)', border: '1px solid var(--border-faint)',
                 borderRadius: 99, padding: '5px 14px', cursor: 'pointer', fontFamily: 'inherit',
@@ -181,7 +181,7 @@ export function ChatMessages(props: any) {
                         transition: 'opacity .1s',
                         ...(own ? { left: -6 } : { right: -6 }),
                       }}>
-                        <button onClick={() => setReplyTo(msg)} title={t('collab.chat.reply')} style={{
+                        <button type="button" onClick={() => setReplyTo(msg)} title={t('collab.chat.reply')} style={{
                           width: 24, height: 24, borderRadius: '50%', border: 'none',
                           background: 'var(--accent)', display: 'flex', alignItems: 'center', justifyContent: 'center',
                           cursor: 'pointer', color: 'var(--accent-text)', padding: 0,
@@ -193,7 +193,7 @@ export function ChatMessages(props: any) {
                           <Reply size={11} />
                         </button>
                         {own && canEdit && (
-                          <button onClick={() => handleDelete(msg.id)} title={t('common.delete')} style={{
+                          <button type="button" onClick={() => handleDelete(msg.id)} title={t('common.delete')} style={{
                             width: 24, height: 24, borderRadius: '50%', border: 'none',
                             background: 'var(--accent)', display: 'flex', alignItems: 'center', justifyContent: 'center',
                             cursor: 'pointer', color: 'var(--accent-text)', padding: 0,
diff --git a/client/src/components/Collab/CollabChatReactionBadge.tsx b/client/src/components/Collab/CollabChatReactionBadge.tsx
index ba773e5ab..e58ac28ea 100644
--- a/client/src/components/Collab/CollabChatReactionBadge.tsx
+++ b/client/src/components/Collab/CollabChatReactionBadge.tsx
@@ -18,7 +18,7 @@ export function ReactionBadge({ reaction, currentUserId, onReact }: ReactionBadg
 
   return (
     <>
-      <button ref={ref} onClick={onReact}
+      <button type="button" ref={ref} onClick={onReact}
         onMouseEnter={() => {
           if (ref.current) {
             const rect = ref.current.getBoundingClientRect()
diff --git a/client/src/components/Collab/CollabChatReactionMenu.tsx b/client/src/components/Collab/CollabChatReactionMenu.tsx
index 57e74a1e1..664ae4526 100644
--- a/client/src/components/Collab/CollabChatReactionMenu.tsx
+++ b/client/src/components/Collab/CollabChatReactionMenu.tsx
@@ -31,7 +31,7 @@ export function ReactionMenu({ x, y, onReact, onClose }: ReactionMenuProps) {
       display: 'grid', gridTemplateColumns: 'repeat(4, 1fr)', gap: 2, width: menuWidth,
     }}>
       {QUICK_REACTIONS.map(emoji => (
-        <button key={emoji} onClick={() => onReact(emoji)} style={{
+        <button type="button" key={emoji} onClick={() => onReact(emoji)} style={{
           width: 30, height: 30, display: 'flex', alignItems: 'center', justifyContent: 'center',
           background: 'none', border: 'none', cursor: 'pointer', borderRadius: '50%',
           padding: 3, transition: 'transform 0.1s, background 0.1s',
diff --git a/client/src/components/Collab/CollabNotes.tsx b/client/src/components/Collab/CollabNotes.tsx
index db3a7b871..fe484c6ff 100644
--- a/client/src/components/Collab/CollabNotes.tsx
+++ b/client/src/components/Collab/CollabNotes.tsx
@@ -303,13 +303,13 @@ function CollabNotesHeader({ t, canEdit, setShowSettings, setShowNewModal }: Not
         {t('collab.notes.title')}
       </h3>
       <div style={{ display: 'flex', gap: 4, alignItems: 'center' }}>
-        {canEdit && <button onClick={() => setShowSettings(true)} title={t('collab.notes.categorySettings')}
+        {canEdit && <button type="button" onClick={() => setShowSettings(true)} title={t('collab.notes.categorySettings')}
           style={{ display: 'flex', alignItems: 'center', justifyContent: 'center', width: 28, height: 28, borderRadius: 8, border: 'none', background: 'transparent', cursor: 'pointer', color: 'var(--text-faint)', transition: 'color 0.12s' }}
           onMouseEnter={e => e.currentTarget.style.color = 'var(--text-primary)'}
           onMouseLeave={e => e.currentTarget.style.color = 'var(--text-faint)'}>
           <Settings size={14} />
         </button>}
-        {canEdit && <button onClick={() => setShowNewModal(true)}
+        {canEdit && <button type="button" onClick={() => setShowNewModal(true)}
           style={{ display: 'inline-flex', alignItems: 'center', gap: 4, borderRadius: 99, padding: '6px 12px', background: 'var(--accent)', color: 'var(--accent-text)', fontSize: 'calc(11px * var(--fs-scale-caption, 1))', fontWeight: 600, fontFamily: FONT, border: 'none', cursor: 'pointer', whiteSpace: 'nowrap' }}>
           <Plus size={12} />
           {t('collab.notes.new')}
@@ -322,7 +322,7 @@ function CollabNotesHeader({ t, canEdit, setShowSettings, setShowNewModal }: Not
 function CollabCategoryPills({ categories, activeCategory, setActiveCategory, t }: NotesState) {
   return (
     <div style={{ display: 'flex', gap: 4, padding: '8px 12px 0', overflowX: 'auto', flexShrink: 0 }}>
-      <button
+      <button type="button"
         onClick={() => setActiveCategory(null)}
         style={{
           flexShrink: 0, borderRadius: 99, padding: '3px 10px', fontSize: 'calc(10px * var(--fs-scale-caption, 1))', fontWeight: 600, fontFamily: FONT,
@@ -335,7 +335,7 @@ function CollabCategoryPills({ categories, activeCategory, setActiveCategory, t
         {t('collab.notes.all')}
       </button>
       {categories.map(cat => (
-        <button
+        <button type="button"
           key={cat}
           onClick={() => setActiveCategory(prev => prev === cat ? null : cat)}
           style={{
@@ -430,13 +430,13 @@ function ViewNoteModal(S: NotesState) {
             )}
           </div>
           <div style={{ display: 'flex', gap: 4, flexShrink: 0 }}>
-            {canEdit && <button onClick={() => { setViewingNote(null); setEditingNote(viewingNote) }}
+            {canEdit && <button type="button" onClick={() => { setViewingNote(null); setEditingNote(viewingNote) }}
               style={{ padding: 6, background: 'none', border: 'none', cursor: 'pointer', color: 'var(--text-faint)', display: 'flex', borderRadius: 6 }}
               onMouseEnter={e => e.currentTarget.style.color = 'var(--text-primary)'}
               onMouseLeave={e => e.currentTarget.style.color = 'var(--text-faint)'}>
               <Pencil size={16} />
             </button>}
-            <button onClick={() => setViewingNote(null)}
+            <button type="button" onClick={() => setViewingNote(null)}
               style={{ padding: 6, background: 'none', border: 'none', cursor: 'pointer', color: 'var(--text-faint)', display: 'flex', borderRadius: 6 }}
               onMouseEnter={e => e.currentTarget.style.color = 'var(--text-primary)'}
               onMouseLeave={e => e.currentTarget.style.color = 'var(--text-faint)'}>
diff --git a/client/src/components/Collab/CollabNotesCard.tsx b/client/src/components/Collab/CollabNotesCard.tsx
index e9fae8547..1b3baaaa2 100644
--- a/client/src/components/Collab/CollabNotesCard.tsx
+++ b/client/src/components/Collab/CollabNotesCard.tsx
@@ -80,26 +80,26 @@ export function NoteCard({ note, currentUser, canEdit, onUpdate, onDelete, onEdi
             display: 'flex', gap: 2,
           }}>
             {note.content && (
-              <button onClick={() => onView?.(note)} title={t('collab.notes.expand') || 'Expand'}
+              <button type="button" onClick={() => onView?.(note)} title={t('collab.notes.expand') || 'Expand'}
                 style={{ padding: 3, background: 'none', border: 'none', cursor: 'pointer', color: 'var(--text-faint)', display: 'flex' }}
                 onMouseEnter={e => e.currentTarget.style.color = 'var(--text-primary)'}
                 onMouseLeave={e => e.currentTarget.style.color = 'var(--text-faint)'}>
                 <Maximize2 size={10} />
               </button>
             )}
-            {canEdit && <button onClick={handleTogglePin} title={note.pinned ? t('collab.notes.unpin') : t('collab.notes.pin')}
+            {canEdit && <button type="button" onClick={handleTogglePin} title={note.pinned ? t('collab.notes.unpin') : t('collab.notes.pin')}
               style={{ padding: 3, background: 'none', border: 'none', cursor: 'pointer', color: 'var(--text-faint)', display: 'flex' }}
               onMouseEnter={e => e.currentTarget.style.color = color}
               onMouseLeave={e => e.currentTarget.style.color = 'var(--text-faint)'}>
               {note.pinned ? <PinOff size={10} /> : <Pin size={10} />}
             </button>}
-            {canEdit && <button onClick={() => onEdit?.(note)} title={t('collab.notes.edit')}
+            {canEdit && <button type="button" onClick={() => onEdit?.(note)} title={t('collab.notes.edit')}
               style={{ padding: 3, background: 'none', border: 'none', cursor: 'pointer', color: 'var(--text-faint)', display: 'flex' }}
               onMouseEnter={e => e.currentTarget.style.color = 'var(--text-primary)'}
               onMouseLeave={e => e.currentTarget.style.color = 'var(--text-faint)'}>
               <Pencil size={10} />
             </button>}
-            {canEdit && <button onClick={handleDelete} title={t('collab.notes.delete')}
+            {canEdit && <button type="button" onClick={handleDelete} title={t('collab.notes.delete')}
               style={{ padding: 3, background: 'none', border: 'none', cursor: 'pointer', color: 'var(--text-faint)', display: 'flex' }}
               onMouseEnter={e => e.currentTarget.style.color = '#ef4444'}
               onMouseLeave={e => e.currentTarget.style.color = 'var(--text-faint)'}>
diff --git a/client/src/components/Collab/CollabNotesCategorySettingsModal.tsx b/client/src/components/Collab/CollabNotesCategorySettingsModal.tsx
index c54a79ff7..2f8a856ea 100644
--- a/client/src/components/Collab/CollabNotesCategorySettingsModal.tsx
+++ b/client/src/components/Collab/CollabNotesCategorySettingsModal.tsx
@@ -79,7 +79,7 @@ export function CategorySettingsModal({ onClose, categories, categoryColors, onS
           <h3 style={{ fontSize: 'calc(14px * var(--fs-scale-body, 1))', fontWeight: 700, color: 'var(--text-primary)', margin: 0 }}>
             {t('collab.notes.categorySettings') || 'Category Settings'}
           </h3>
-          <button onClick={onClose} style={{ background: 'none', border: 'none', cursor: 'pointer', color: 'var(--text-faint)', padding: 2, display: 'flex' }}>
+          <button type="button" onClick={onClose} style={{ background: 'none', border: 'none', cursor: 'pointer', color: 'var(--text-faint)', padding: 2, display: 'flex' }}>
             <X size={16} />
           </button>
         </div>
@@ -96,7 +96,7 @@ export function CategorySettingsModal({ onClose, categories, categoryColors, onS
               {/* Color swatches */}
               <div style={{ display: 'flex', gap: 4 }}>
                 {NOTE_COLORS.map(c => (
-                  <button key={c.value} onClick={() => handleColorChange(cat, c.value)} style={{
+                  <button type="button" key={c.value} onClick={() => handleColorChange(cat, c.value)} style={{
                     width: 20, height: 20, borderRadius: 6, background: c.value, border: 'none', cursor: 'pointer', padding: 0,
                     outline: (localColors[cat] || NOTE_COLORS[0].value) === c.value ? '2px solid var(--text-primary)' : '2px solid transparent',
                     outlineOffset: 1, transition: 'transform 0.1s',
@@ -107,7 +107,7 @@ export function CategorySettingsModal({ onClose, categories, categoryColors, onS
               {/* Category name — editable */}
               <EditableCatName name={cat} onRename={(newName) => handleRenameCategory(cat, newName)} />
               {/* Delete */}
-              <button onClick={() => handleRemoveCategory(cat)} style={{
+              <button type="button" onClick={() => handleRemoveCategory(cat)} style={{
                 background: 'none', border: 'none', cursor: 'pointer', color: 'var(--text-faint)', padding: 3, display: 'flex',
               }}
                 onMouseEnter={e => e.currentTarget.style.color = '#ef4444'}
@@ -126,7 +126,7 @@ export function CategorySettingsModal({ onClose, categories, categoryColors, onS
                 flex: 1, border: '1px solid var(--border-primary)', borderRadius: 10, padding: '8px 12px',
                 fontSize: 'calc(13px * var(--fs-scale-body, 1))', background: 'var(--bg-input)', color: 'var(--text-primary)', fontFamily: 'inherit', outline: 'none',
               }} />
-            <button onClick={handleAddCategory} disabled={!newCatName.trim()} style={{
+            <button type="button" onClick={handleAddCategory} disabled={!newCatName.trim()} style={{
               background: newCatName.trim() ? 'var(--accent)' : 'var(--border-primary)', color: 'var(--accent-text)',
               border: 'none', borderRadius: 10, padding: '8px 14px', cursor: newCatName.trim() ? 'pointer' : 'default',
               display: 'flex', alignItems: 'center', flexShrink: 0,
@@ -136,7 +136,7 @@ export function CategorySettingsModal({ onClose, categories, categoryColors, onS
           </div>
 
           {/* Save */}
-          <button onClick={handleSave} style={{
+          <button type="button" onClick={handleSave} style={{
             width: '100%', borderRadius: 99, padding: '9px 14px', background: 'var(--accent)', color: 'var(--accent-text)',
             fontSize: 'calc(13px * var(--fs-scale-body, 1))', fontWeight: 600, border: 'none', cursor: 'pointer', marginTop: 8,
           }}>
diff --git a/client/src/components/Collab/CollabNotesFilePreviewPortal.tsx b/client/src/components/Collab/CollabNotesFilePreviewPortal.tsx
index 78d2c9150..f1098b8ba 100644
--- a/client/src/components/Collab/CollabNotesFilePreviewPortal.tsx
+++ b/client/src/components/Collab/CollabNotesFilePreviewPortal.tsx
@@ -39,8 +39,8 @@ export function FilePreviewPortal({ file, onClose }: FilePreviewPortalProps) {
           <div style={{ position: 'absolute', top: -36, left: 0, right: 0, display: 'flex', alignItems: 'center', justifyContent: 'space-between', padding: '0 4px' }}>
             <span style={{ fontSize: 'calc(11px * var(--fs-scale-caption, 1))', color: 'rgba(255,255,255,0.7)', overflow: 'hidden', textOverflow: 'ellipsis', whiteSpace: 'nowrap', maxWidth: '70%' }}>{file.original_name}</span>
             <div style={{ display: 'flex', gap: 8 }}>
-              <button onClick={openInNewTab} style={{ background: 'none', border: 'none', cursor: 'pointer', color: 'rgba(255,255,255,0.7)', display: 'flex', padding: 0 }}><ExternalLink size={15} /></button>
-              <button onClick={onClose} style={{ background: 'none', border: 'none', cursor: 'pointer', color: 'rgba(255,255,255,0.7)', display: 'flex', padding: 0 }}><X size={17} /></button>
+              <button type="button" onClick={openInNewTab} style={{ background: 'none', border: 'none', cursor: 'pointer', color: 'rgba(255,255,255,0.7)', display: 'flex', padding: 0 }}><ExternalLink size={15} /></button>
+              <button type="button" onClick={onClose} style={{ background: 'none', border: 'none', cursor: 'pointer', color: 'rgba(255,255,255,0.7)', display: 'flex', padding: 0 }}><X size={17} /></button>
             </div>
           </div>
         </div>
@@ -50,19 +50,19 @@ export function FilePreviewPortal({ file, onClose }: FilePreviewPortalProps) {
           <div style={{ display: 'flex', alignItems: 'center', justifyContent: 'space-between', padding: '10px 16px', borderBottom: '1px solid var(--border-primary)', flexShrink: 0 }}>
             <span style={{ fontSize: 'calc(13px * var(--fs-scale-body, 1))', fontWeight: 600, color: 'var(--text-primary)', overflow: 'hidden', textOverflow: 'ellipsis', whiteSpace: 'nowrap', flex: 1 }}>{file.original_name}</span>
             <div style={{ display: 'flex', gap: 8, flexShrink: 0 }}>
-              <button onClick={openInNewTab} style={{ background: 'none', border: 'none', cursor: 'pointer', display: 'flex', alignItems: 'center', gap: 3, fontSize: 'calc(11px * var(--fs-scale-caption, 1))', color: 'var(--text-muted)', padding: 0 }}><ExternalLink size={13} /></button>
-              <button onClick={onClose} style={{ background: 'none', border: 'none', cursor: 'pointer', color: 'var(--text-faint)', display: 'flex', padding: 2 }}><X size={18} /></button>
+              <button type="button" onClick={openInNewTab} style={{ background: 'none', border: 'none', cursor: 'pointer', display: 'flex', alignItems: 'center', gap: 3, fontSize: 'calc(11px * var(--fs-scale-caption, 1))', color: 'var(--text-muted)', padding: 0 }}><ExternalLink size={13} /></button>
+              <button type="button" onClick={onClose} style={{ background: 'none', border: 'none', cursor: 'pointer', color: 'var(--text-faint)', display: 'flex', padding: 2 }}><X size={18} /></button>
             </div>
           </div>
           {(isPdf || isTxt) ? (
             <object data={authUrl ? `${authUrl}#view=FitH` : ''} type={file.mime_type} style={{ flex: 1, width: '100%', border: 'none', background: '#fff' }} title={file.original_name}>
               <p style={{ padding: 24, textAlign: 'center', color: 'var(--text-muted)' }}>
-                <button onClick={openInNewTab} style={{ background: 'none', border: 'none', cursor: 'pointer', color: 'var(--text-primary)', textDecoration: 'underline', fontSize: 'calc(14px * var(--fs-scale-body, 1))', padding: 0 }}>Download</button>
+                <button type="button" onClick={openInNewTab} style={{ background: 'none', border: 'none', cursor: 'pointer', color: 'var(--text-primary)', textDecoration: 'underline', fontSize: 'calc(14px * var(--fs-scale-body, 1))', padding: 0 }}>Download</button>
               </p>
             </object>
           ) : (
             <div style={{ flex: 1, display: 'flex', alignItems: 'center', justifyContent: 'center', padding: 40 }}>
-              <button onClick={openInNewTab} style={{ background: 'none', border: 'none', cursor: 'pointer', color: 'var(--text-primary)', textDecoration: 'underline', fontSize: 'calc(14px * var(--fs-scale-body, 1))', padding: 0 }}>Download {file.original_name}</button>
+              <button type="button" onClick={openInNewTab} style={{ background: 'none', border: 'none', cursor: 'pointer', color: 'var(--text-primary)', textDecoration: 'underline', fontSize: 'calc(14px * var(--fs-scale-body, 1))', padding: 0 }}>Download {file.original_name}</button>
             </div>
           )}
         </div>
diff --git a/client/src/components/Collab/CollabPanel.tsx b/client/src/components/Collab/CollabPanel.tsx
index e75f5e3f2..98100b01b 100644
--- a/client/src/components/Collab/CollabPanel.tsx
+++ b/client/src/components/Collab/CollabPanel.tsx
@@ -170,7 +170,7 @@ export default function CollabPanel({ tripId, tripMembers = [], collabFeatures }
         {tabs.map(tab => {
           const active = mobileTab === tab.id
           return (
-            <button key={tab.id} onClick={() => setMobileTab(tab.id)} style={{
+            <button type="button" key={tab.id} onClick={() => setMobileTab(tab.id)} style={{
               flex: 1, display: 'flex', alignItems: 'center', justifyContent: 'center', gap: 6,
               padding: '8px 0', borderRadius: 10, border: 'none', cursor: 'pointer',
               background: active ? 'var(--accent)' : 'transparent',
diff --git a/client/src/components/Collab/CollabPolls.tsx b/client/src/components/Collab/CollabPolls.tsx
index f2b181a59..564ded94b 100644
--- a/client/src/components/Collab/CollabPolls.tsx
+++ b/client/src/components/Collab/CollabPolls.tsx
@@ -250,14 +250,14 @@ function PollCard({ poll, currentUser, canEdit, onVote, onClose, onDelete, t }:
         {canEdit && (
           <div style={{ display: 'flex', gap: 2, flexShrink: 0 }}>
             {!isClosed && (
-              <button onClick={() => onClose(poll.id)} title={t('collab.polls.close')}
+              <button type="button" onClick={() => onClose(poll.id)} title={t('collab.polls.close')}
                 style={{ padding: 4, background: 'none', border: 'none', cursor: 'pointer', color: 'var(--text-faint)', display: 'flex', borderRadius: 6 }}
                 onMouseEnter={e => e.currentTarget.style.color = 'var(--text-primary)'}
                 onMouseLeave={e => e.currentTarget.style.color = 'var(--text-faint)'}>
                 <Lock size={12} />
               </button>
             )}
-            <button onClick={() => onDelete(poll.id)} title={t('collab.polls.delete')}
+            <button type="button" onClick={() => onDelete(poll.id)} title={t('collab.polls.delete')}
               style={{ padding: 4, background: 'none', border: 'none', cursor: 'pointer', color: 'var(--text-faint)', display: 'flex', borderRadius: 6 }}
               onMouseEnter={e => e.currentTarget.style.color = '#ef4444'}
               onMouseLeave={e => e.currentTarget.style.color = 'var(--text-faint)'}>
@@ -278,7 +278,7 @@ function PollCard({ poll, currentUser, canEdit, onVote, onClose, onDelete, t }:
           return (
             // React dispatches no mouse events on a disabled control, so the
             // handlers below need no isClosed guard of their own.
-            <button key={idx} onClick={() => onVote(poll.id, idx)}
+            <button type="button" key={idx} onClick={() => onVote(poll.id, idx)}
               disabled={isClosed}
               style={{
                 position: 'relative', display: 'flex', alignItems: 'center', gap: 8,
@@ -465,7 +465,7 @@ export default function CollabPolls({ tripId, currentUser }: CollabPollsProps) {
           {t('collab.polls.title')}
         </h3>
         {canEdit && (
-          <button onClick={() => setShowForm(true)} style={{
+          <button type="button" onClick={() => setShowForm(true)} style={{
             display: 'inline-flex', alignItems: 'center', gap: 4, borderRadius: 99, padding: '6px 12px',
             background: 'var(--accent)', color: 'var(--accent-text)', fontSize: 'calc(11px * var(--fs-scale-caption, 1))', fontWeight: 600,
             fontFamily: FONT, border: 'none', cursor: 'pointer',
diff --git a/client/src/components/Collections/AddPlaceToCollectionModal.tsx b/client/src/components/Collections/AddPlaceToCollectionModal.tsx
index da2117dc8..967b98fd1 100644
--- a/client/src/components/Collections/AddPlaceToCollectionModal.tsx
+++ b/client/src/components/Collections/AddPlaceToCollectionModal.tsx
@@ -97,8 +97,8 @@ export default function AddPlaceToCollectionModal({ isOpen, collectionId, collec
     const cleanName = name.trim()
     if (!cleanName) return
     const cleanLinks = links.map(l => ({ label: l.label?.trim() || undefined, url: normalizeLinkUrl(l.url) })).filter(l => l.url)
-    const latNum = lat.trim() ? Number(lat) : NaN
-    const lngNum = lng.trim() ? Number(lng) : NaN
+    const latNum = lat.trim() ? Number(lat) : Number.NaN
+    const lngNum = lng.trim() ? Number(lng) : Number.NaN
     setSaving(true)
     try {
       const res = await collectionsApi.savePlace({
diff --git a/client/src/components/Collections/CollectionPlaceDetail.tsx b/client/src/components/Collections/CollectionPlaceDetail.tsx
index 7a3166b50..46c239827 100644
--- a/client/src/components/Collections/CollectionPlaceDetail.tsx
+++ b/client/src/components/Collections/CollectionPlaceDetail.tsx
@@ -159,8 +159,8 @@ export default function CollectionPlaceDetail({
 
   const save = async () => {
     const cleanLinks = links.map(l => ({ label: l.label?.trim() || undefined, url: normalizeLinkUrl(l.url) })).filter(l => l.url)
-    const latNum = lat.trim() ? Number(lat) : NaN
-    const lngNum = lng.trim() ? Number(lng) : NaN
+    const latNum = lat.trim() ? Number(lat) : Number.NaN
+    const lngNum = lng.trim() ? Number(lng) : Number.NaN
     setSaving(true)
     try {
       await onSave({ name: name.trim() || place.name, description: description.trim() || null, links: cleanLinks, category_id: categoryId, label_ids: labelIds, address: address.trim() || null, lat: Number.isFinite(latNum) ? latNum : null, lng: Number.isFinite(lngNum) ? lngNum : null })
diff --git a/client/src/components/Collections/StatusBadge.tsx b/client/src/components/Collections/StatusBadge.tsx
index a118ce511..3b79bc72d 100644
--- a/client/src/components/Collections/StatusBadge.tsx
+++ b/client/src/components/Collections/StatusBadge.tsx
@@ -51,7 +51,7 @@ export default function StatusBadge({ status, onChange, showLabel = true, size =
     return <span className={className} title={label}>{content}</span>
   }
 
-  // Rendered as a role=button span (not a native <button>) on purpose: inside
+  // Rendered as a role=button span (not a native <button type="button">) on purpose: inside
   // the .trek-dash scope the global `.trek-dash button` reset would strip the
   // pill's background/border/padding, and the pill also has to sit inside the
   // grid card's own clickable element without nesting one button in another.
diff --git a/client/src/components/Dashboard/CollectionsWidget.tsx b/client/src/components/Dashboard/CollectionsWidget.tsx
index e71ce152a..ea8963c2f 100644
--- a/client/src/components/Dashboard/CollectionsWidget.tsx
+++ b/client/src/components/Dashboard/CollectionsWidget.tsx
@@ -38,7 +38,7 @@ export default function CollectionsWidget({ onOpen }: { onOpen: () => void }): R
     <div className="tool">
       <div className="tool-head">
         <div className="tool-title"><Bookmark size={14} /> {t('collections.widget.title')}</div>
-        <button className="tool-action" aria-label={t('collections.widget.title')} onClick={onOpen}>
+        <button type="button" className="tool-action" aria-label={t('collections.widget.title')} onClick={onOpen}>
           <ArrowRight size={14} />
         </button>
       </div>
@@ -47,7 +47,7 @@ export default function CollectionsWidget({ onOpen }: { onOpen: () => void }): R
       ) : (
         <div className="col-badges">
           {lists.slice(0, 6).map(list => (
-            <button
+            <button type="button"
               key={list.id}
               className="col-badge"
               style={{ ['--badge-color' as string]: list.color || '#6366f1' }}
diff --git a/client/src/components/Files/FileManagerAssignModal.tsx b/client/src/components/Files/FileManagerAssignModal.tsx
index c92ed629e..e47dfc299 100644
--- a/client/src/components/Files/FileManagerAssignModal.tsx
+++ b/client/src/components/Files/FileManagerAssignModal.tsx
@@ -22,7 +22,7 @@ export function AssignModal(S: FileManagerState) {
               {files.find(f => f.id === assignFileId)?.original_name || ''}
             </div>
           </div>
-          <button onClick={() => setAssignFileId(null)} style={{ background: 'none', border: 'none', cursor: 'pointer', color: 'var(--text-faint)', padding: 4, display: 'flex', flexShrink: 0 }}>
+          <button type="button" onClick={() => setAssignFileId(null)} style={{ background: 'none', border: 'none', cursor: 'pointer', color: 'var(--text-faint)', padding: 4, display: 'flex', flexShrink: 0 }}>
             <X size={18} />
           </button>
         </div>
@@ -67,7 +67,7 @@ export function AssignModal(S: FileManagerState) {
             const placeBtn = (p: Place, idx: number) => {
               const isLinked = file.place_id === p.id || (file.linked_place_ids || []).includes(p.id)
               return (
-                <button key={`${p.id}-${idx}`} onClick={async () => {
+                <button type="button" key={`${p.id}-${idx}`} onClick={async () => {
                   if (isLinked) {
                     if (file.place_id === p.id) {
                       await handleAssign(file.id, { place_id: null })
@@ -142,7 +142,7 @@ export function AssignModal(S: FileManagerState) {
               const isLinked = file.reservation_id === r.id || (file.linked_reservation_ids || []).includes(r.id)
               const Icon = TRANSPORT_TYPES.has(r.type) ? transportIcon(r.type) : Ticket
               return (
-                <button key={r.id} onClick={async () => {
+                <button type="button" key={r.id} onClick={async () => {
                   if (isLinked) {
                     if (file.reservation_id === r.id) {
                       await handleAssign(file.id, { reservation_id: null })
diff --git a/client/src/components/Files/FileManagerFilesView.tsx b/client/src/components/Files/FileManagerFilesView.tsx
index 377db7102..20fbd26cf 100644
--- a/client/src/components/Files/FileManagerFilesView.tsx
+++ b/client/src/components/Files/FileManagerFilesView.tsx
@@ -51,7 +51,7 @@ export function FilesView(S: FileManagerState) {
           { id: 'doc', label: t('files.filterDocs') },
           ...(files.some(f => f.note_id) ? [{ id: 'collab', label: t('files.filterCollab') || 'Collab' }] : []),
         ].map(tab => (
-          <button key={tab.id} onClick={() => setFilterType(tab.id)} style={{
+          <button type="button" key={tab.id} onClick={() => setFilterType(tab.id)} style={{
             padding: '4px 12px', borderRadius: 99, border: 'none', cursor: 'pointer', fontSize: 'calc(12px * var(--fs-scale-body, 1))',
             fontFamily: 'inherit', transition: 'all 0.12s',
             background: filterType === tab.id ? 'var(--accent)' : 'transparent',
diff --git a/client/src/components/Files/FileManagerImageLightbox.tsx b/client/src/components/Files/FileManagerImageLightbox.tsx
index aa497850b..d77e19bcd 100644
--- a/client/src/components/Files/FileManagerImageLightbox.tsx
+++ b/client/src/components/Files/FileManagerImageLightbox.tsx
@@ -53,7 +53,7 @@ export function ImageLightbox({ files, initialIndex, onClose }: ImageLightboxPro
   const hasPrev = index > 0
   const hasNext = index < files.length - 1
   const navBtn = (side: 'left' | 'right', onClick: () => void, show: boolean): React.ReactNode => show ? (
-    <button onClick={e => { e.stopPropagation(); onClick() }}
+    <button type="button" onClick={e => { e.stopPropagation(); onClick() }}
       style={{
         position: 'absolute', top: '50%', [side]: 12, transform: 'translateY(-50%)', zIndex: 10,
         background: 'rgba(0,0,0,0.5)', border: 'none', borderRadius: '50%', width: 40, height: 40,
@@ -86,19 +86,19 @@ export function ImageLightbox({ files, initialIndex, onClose }: ImageLightboxPro
           <span style={{ marginLeft: 8, color: 'rgba(255,255,255,0.4)' }}>{index + 1} / {files.length}</span>
         </span>
         <div style={{ display: 'flex', gap: 8, flexShrink: 0 }}>
-          <button
+          <button type="button"
             onClick={() => openFileUrl(file.url, file.original_name).catch(() => {})}
             style={{ background: 'none', border: 'none', cursor: 'pointer', color: 'rgba(255,255,255,0.7)', display: 'flex', padding: 4 }}
             title={t('files.openTab')}>
             <ExternalLink size={16} />
           </button>
-          <button
+          <button type="button"
             onClick={() => triggerDownload(file.url, file.original_name)}
             style={{ background: 'none', border: 'none', cursor: 'pointer', color: 'rgba(255,255,255,0.7)', display: 'flex', padding: 4 }}
             title={t('files.download') || 'Download'}>
             <Download size={16} />
           </button>
-          <button onClick={onClose} style={{ background: 'none', border: 'none', cursor: 'pointer', color: 'rgba(255,255,255,0.7)', display: 'flex', padding: 4 }}>
+          <button type="button" onClick={onClose} style={{ background: 'none', border: 'none', cursor: 'pointer', color: 'rgba(255,255,255,0.7)', display: 'flex', padding: 4 }}>
             <X size={18} />
           </button>
         </div>
@@ -156,7 +156,7 @@ function ThumbImg({ file, active, onClick }: { file: TripFile & { url: string };
   }, [file.url, fileIsVideo, visible])
 
   return (
-    <button ref={ref} onClick={onClick} style={{
+    <button type="button" ref={ref} onClick={onClick} style={{
       width: 48, height: 48, borderRadius: 6, overflow: 'hidden', border: active ? '2px solid #fff' : '2px solid transparent',
       opacity: active ? 1 : 0.5, cursor: 'pointer', padding: 0, background: '#111', flexShrink: 0, transition: 'opacity 0.15s',
       display: 'flex', alignItems: 'center', justifyContent: 'center', color: 'rgba(255,255,255,0.7)',
diff --git a/client/src/components/Files/FileManagerMarkdownPreviewModal.tsx b/client/src/components/Files/FileManagerMarkdownPreviewModal.tsx
index bfab94991..b13eb1407 100644
--- a/client/src/components/Files/FileManagerMarkdownPreviewModal.tsx
+++ b/client/src/components/Files/FileManagerMarkdownPreviewModal.tsx
@@ -44,17 +44,17 @@ export function MarkdownPreviewModal(S: FileManagerState) {
         <div style={{ display: 'flex', alignItems: 'center', justifyContent: 'space-between', padding: '10px 16px', borderBottom: '1px solid var(--border-primary)', flexShrink: 0 }}>
           <span style={{ fontSize: 'calc(13px * var(--fs-scale-body, 1))', fontWeight: 600, color: 'var(--text-primary)', overflow: 'hidden', textOverflow: 'ellipsis', whiteSpace: 'nowrap', flex: 1 }}>{previewFile.original_name}</span>
           <div style={{ display: 'flex', alignItems: 'center', gap: 8, flexShrink: 0 }}>
-            <button
+            <button type="button"
               onClick={() => openFileUrl(previewFile.url, previewFile.original_name).catch(() => toast.error(t('files.openError')))}
               style={{ display: 'flex', alignItems: 'center', gap: 4, fontSize: 'calc(12px * var(--fs-scale-body, 1))', color: 'var(--text-muted)', background: 'none', border: 'none', cursor: 'pointer', padding: '4px 8px', borderRadius: 6 }}>
               <ExternalLink size={13} /> {t('files.openTab')}
             </button>
-            <button
+            <button type="button"
               onClick={() => triggerDownload(previewFile.url, previewFile.original_name)}
               style={{ display: 'flex', alignItems: 'center', gap: 4, fontSize: 'calc(12px * var(--fs-scale-body, 1))', color: 'var(--text-muted)', background: 'none', border: 'none', cursor: 'pointer', padding: '4px 8px', borderRadius: 6 }}>
               <Download size={13} /> {t('files.download') || 'Download'}
             </button>
-            <button onClick={() => setPreviewFile(null)}
+            <button type="button" onClick={() => setPreviewFile(null)}
               style={{ background: 'none', border: 'none', cursor: 'pointer', color: 'var(--text-faint)', display: 'flex', padding: 4, borderRadius: 6 }}>
               <X size={18} />
             </button>
diff --git a/client/src/components/Files/FileManagerPdfPreviewModal.tsx b/client/src/components/Files/FileManagerPdfPreviewModal.tsx
index 9c3c97f54..55932dc27 100644
--- a/client/src/components/Files/FileManagerPdfPreviewModal.tsx
+++ b/client/src/components/Files/FileManagerPdfPreviewModal.tsx
@@ -18,21 +18,21 @@ export function PdfPreviewModal(S: FileManagerState) {
         <div style={{ display: 'flex', alignItems: 'center', justifyContent: 'space-between', padding: '10px 16px', borderBottom: '1px solid var(--border-primary)', flexShrink: 0 }}>
           <span style={{ fontSize: 'calc(13px * var(--fs-scale-body, 1))', fontWeight: 600, color: 'var(--text-primary)', overflow: 'hidden', textOverflow: 'ellipsis', whiteSpace: 'nowrap', flex: 1 }}>{previewFile.original_name}</span>
           <div style={{ display: 'flex', alignItems: 'center', gap: 8, flexShrink: 0 }}>
-            <button
+            <button type="button"
               onClick={() => openFileUrl(previewFile.url, previewFile.original_name).catch(() => toast.error(t('files.openError')))}
               style={{ display: 'flex', alignItems: 'center', gap: 4, fontSize: 'calc(12px * var(--fs-scale-body, 1))', color: 'var(--text-muted)', background: 'none', border: 'none', cursor: 'pointer', textDecoration: 'none', padding: '4px 8px', borderRadius: 6, transition: 'color 0.15s' }}
               onMouseEnter={e => (e.currentTarget as HTMLElement).style.color = 'var(--text-primary)'}
               onMouseLeave={e => (e.currentTarget as HTMLElement).style.color = 'var(--text-muted)'}>
               <ExternalLink size={13} /> {t('files.openTab')}
             </button>
-            <button
+            <button type="button"
               onClick={() => triggerDownload(previewFile.url, previewFile.original_name)}
               style={{ display: 'flex', alignItems: 'center', gap: 4, fontSize: 'calc(12px * var(--fs-scale-body, 1))', color: 'var(--text-muted)', background: 'none', border: 'none', cursor: 'pointer', textDecoration: 'none', padding: '4px 8px', borderRadius: 6, transition: 'color 0.15s' }}
               onMouseEnter={e => (e.currentTarget as HTMLElement).style.color = 'var(--text-primary)'}
               onMouseLeave={e => (e.currentTarget as HTMLElement).style.color = 'var(--text-muted)'}>
               <Download size={13} /> {t('files.download') || 'Download'}
             </button>
-            <button onClick={() => setPreviewFile(null)}
+            <button type="button" onClick={() => setPreviewFile(null)}
               style={{ background: 'none', border: 'none', cursor: 'pointer', color: 'var(--text-faint)', display: 'flex', padding: 4, borderRadius: 6, transition: 'color 0.15s' }}
               onMouseEnter={e => e.currentTarget.style.color = 'var(--text-primary)'}
               onMouseLeave={e => e.currentTarget.style.color = 'var(--text-faint)'}>
@@ -47,7 +47,7 @@ export function PdfPreviewModal(S: FileManagerState) {
           title={previewFile.original_name}
         >
           <p style={{ padding: 24, textAlign: 'center', color: 'var(--text-muted)' }}>
-            <button onClick={() => openFileUrl(previewFile.url, previewFile.original_name).catch(() => toast.error(t('files.openError')))} style={{ color: 'var(--text-primary)', textDecoration: 'underline', background: 'none', border: 'none', cursor: 'pointer', font: 'inherit' }}>{t('files.downloadPdf')}</button>
+            <button type="button" onClick={() => openFileUrl(previewFile.url, previewFile.original_name).catch(() => toast.error(t('files.openError')))} style={{ color: 'var(--text-primary)', textDecoration: 'underline', background: 'none', border: 'none', cursor: 'pointer', font: 'inherit' }}>{t('files.downloadPdf')}</button>
           </p>
         </object>
       </div>
diff --git a/client/src/components/Files/FileManagerRow.tsx b/client/src/components/Files/FileManagerRow.tsx
index 79fda174d..861697366 100644
--- a/client/src/components/Files/FileManagerRow.tsx
+++ b/client/src/components/Files/FileManagerRow.tsx
@@ -97,34 +97,34 @@ export function FileRow(p: FileManagerState & { file: TripFile; isTrash?: boolea
       <div className="file-actions" style={{ display: 'flex', gap: 2, flexShrink: 0 }}>
         {isTrash ? (
           <>
-            {can('file_delete', trip) && <button onClick={() => handleRestore(file.id)} title={t('files.restore') || 'Restore'} style={{ padding: 6, background: 'none', border: 'none', cursor: 'pointer', color: 'var(--text-faint)', borderRadius: 6, display: 'flex' }}
+            {can('file_delete', trip) && <button type="button" onClick={() => handleRestore(file.id)} title={t('files.restore') || 'Restore'} style={{ padding: 6, background: 'none', border: 'none', cursor: 'pointer', color: 'var(--text-faint)', borderRadius: 6, display: 'flex' }}
               onMouseEnter={e => e.currentTarget.style.color = '#22c55e'} onMouseLeave={e => e.currentTarget.style.color = 'var(--text-faint)'}>
               <RotateCcw size={14} />
             </button>}
-            {can('file_delete', trip) && <button onClick={() => handlePermanentDelete(file.id)} title={t('common.delete')} style={{ padding: 6, background: 'none', border: 'none', cursor: 'pointer', color: 'var(--text-faint)', borderRadius: 6, display: 'flex' }}
+            {can('file_delete', trip) && <button type="button" onClick={() => handlePermanentDelete(file.id)} title={t('common.delete')} style={{ padding: 6, background: 'none', border: 'none', cursor: 'pointer', color: 'var(--text-faint)', borderRadius: 6, display: 'flex' }}
               onMouseEnter={e => e.currentTarget.style.color = '#ef4444'} onMouseLeave={e => e.currentTarget.style.color = 'var(--text-faint)'}>
               <Trash2 size={14} />
             </button>}
           </>
         ) : (
           <>
-            <button onClick={() => handleStar(file.id)} title={file.starred ? t('files.unstar') || 'Unstar' : t('files.star') || 'Star'} style={{ padding: 6, background: 'none', border: 'none', cursor: 'pointer', color: file.starred ? '#facc15' : 'var(--text-faint)', borderRadius: 6, display: 'flex' }}
+            <button type="button" onClick={() => handleStar(file.id)} title={file.starred ? t('files.unstar') || 'Unstar' : t('files.star') || 'Star'} style={{ padding: 6, background: 'none', border: 'none', cursor: 'pointer', color: file.starred ? '#facc15' : 'var(--text-faint)', borderRadius: 6, display: 'flex' }}
               onMouseEnter={e => { if (!file.starred) e.currentTarget.style.color = '#facc15' }} onMouseLeave={e => { if (!file.starred) e.currentTarget.style.color = 'var(--text-faint)' }}>
               <Star size={14} fill={file.starred ? '#facc15' : 'none'} />
             </button>
-            {can('file_edit', trip) && <button onClick={() => setAssignFileId(file.id)} title={t('files.assign') || 'Assign'} style={{ padding: 6, background: 'none', border: 'none', cursor: 'pointer', color: 'var(--text-faint)', borderRadius: 6, display: 'flex' }}
+            {can('file_edit', trip) && <button type="button" onClick={() => setAssignFileId(file.id)} title={t('files.assign') || 'Assign'} style={{ padding: 6, background: 'none', border: 'none', cursor: 'pointer', color: 'var(--text-faint)', borderRadius: 6, display: 'flex' }}
               onMouseEnter={e => e.currentTarget.style.color = 'var(--text-primary)'} onMouseLeave={e => e.currentTarget.style.color = 'var(--text-faint)'}>
               <Pencil size={14} />
             </button>}
-            <button onClick={() => openFile(file)} title={t('common.open')} style={{ padding: 6, background: 'none', border: 'none', cursor: 'pointer', color: 'var(--text-faint)', borderRadius: 6, display: 'flex' }}
+            <button type="button" onClick={() => openFile(file)} title={t('common.open')} style={{ padding: 6, background: 'none', border: 'none', cursor: 'pointer', color: 'var(--text-faint)', borderRadius: 6, display: 'flex' }}
               onMouseEnter={e => e.currentTarget.style.color = 'var(--text-primary)'} onMouseLeave={e => e.currentTarget.style.color = 'var(--text-faint)'}>
               <ExternalLink size={14} />
             </button>
-            <button onClick={() => triggerDownload(file.url, file.original_name)} title={t('files.download') || 'Download'} style={{ padding: 6, background: 'none', border: 'none', cursor: 'pointer', color: 'var(--text-faint)', borderRadius: 6, display: 'flex' }}
+            <button type="button" onClick={() => triggerDownload(file.url, file.original_name)} title={t('files.download') || 'Download'} style={{ padding: 6, background: 'none', border: 'none', cursor: 'pointer', color: 'var(--text-faint)', borderRadius: 6, display: 'flex' }}
               onMouseEnter={e => e.currentTarget.style.color = 'var(--text-primary)'} onMouseLeave={e => e.currentTarget.style.color = 'var(--text-faint)'}>
               <Download size={14} />
             </button>
-            {can('file_delete', trip) && <button onClick={() => handleDelete(file.id)} title={t('common.delete')} style={{ padding: 6, background: 'none', border: 'none', cursor: 'pointer', color: 'var(--text-faint)', borderRadius: 6, display: 'flex' }}
+            {can('file_delete', trip) && <button type="button" onClick={() => handleDelete(file.id)} title={t('common.delete')} style={{ padding: 6, background: 'none', border: 'none', cursor: 'pointer', color: 'var(--text-faint)', borderRadius: 6, display: 'flex' }}
               onMouseEnter={e => e.currentTarget.style.color = '#ef4444'} onMouseLeave={e => e.currentTarget.style.color = 'var(--text-faint)'}>
               <Trash2 size={14} />
             </button>}
diff --git a/client/src/components/Files/FileManagerToolbar.tsx b/client/src/components/Files/FileManagerToolbar.tsx
index 085d7626f..2c77017e1 100644
--- a/client/src/components/Files/FileManagerToolbar.tsx
+++ b/client/src/components/Files/FileManagerToolbar.tsx
@@ -36,7 +36,7 @@ export function FileManagerToolbar(S: FileManagerState) {
                   : tab.id === 'collab' ? files.filter(f => f.note_id).length
                   : 0
                 return (
-                  <button key={tab.id} onClick={() => setFilterType(tab.id)}
+                  <button type="button" key={tab.id} onClick={() => setFilterType(tab.id)}
                     style={{
                       appearance: 'none', border: 'none', cursor: 'pointer', fontFamily: 'inherit',
                       display: 'inline-flex', alignItems: 'center', gap: 6,
@@ -63,7 +63,7 @@ export function FileManagerToolbar(S: FileManagerState) {
           </>
         )}
 
-        <button onClick={toggleTrash} style={{
+        <button type="button" onClick={toggleTrash} style={{
           appearance: 'none', border: 'none', cursor: 'pointer', fontFamily: 'inherit',
           display: 'inline-flex', alignItems: 'center', gap: 6,
           padding: '9px 14px', borderRadius: 10, fontSize: 'calc(13px * var(--fs-scale-body, 1))', fontWeight: 500,
diff --git a/client/src/components/Files/FileManagerTrashView.tsx b/client/src/components/Files/FileManagerTrashView.tsx
index 79200768e..1c72a2217 100644
--- a/client/src/components/Files/FileManagerTrashView.tsx
+++ b/client/src/components/Files/FileManagerTrashView.tsx
@@ -8,7 +8,7 @@ export function TrashView(S: FileManagerState) {
     <div style={{ flex: 1, overflowY: 'auto', padding: '12px 16px 16px' }}>
       {trashFiles.length > 0 && can('file_delete', trip) && (
         <div style={{ display: 'flex', justifyContent: 'flex-end', marginBottom: 12 }}>
-          <button onClick={handleEmptyTrash} style={{
+          <button type="button" onClick={handleEmptyTrash} style={{
             padding: '5px 12px', borderRadius: 8, border: '1px solid #fecaca',
             background: '#fef2f2', color: '#dc2626', fontSize: 'calc(12px * var(--fs-scale-body, 1))', fontWeight: 500,
             cursor: 'pointer', fontFamily: 'inherit',
diff --git a/client/src/components/Journey/ContributorInviteDialog.tsx b/client/src/components/Journey/ContributorInviteDialog.tsx
index ff940ca0e..00127f431 100644
--- a/client/src/components/Journey/ContributorInviteDialog.tsx
+++ b/client/src/components/Journey/ContributorInviteDialog.tsx
@@ -49,7 +49,7 @@ export default function ContributorInviteDialog({ journeyId, existingUserIds, on
 
         <div className="flex items-center justify-between px-6 py-4 border-b border-zinc-200 dark:border-zinc-700">
           <h2 className="text-[16px] font-bold text-zinc-900 dark:text-white">{t('journey.contributors.invite')}</h2>
-          <button onClick={onClose} className="w-8 h-8 rounded-lg flex items-center justify-center text-zinc-400 hover:bg-zinc-100 dark:hover:bg-zinc-800">
+          <button type="button" onClick={onClose} className="w-8 h-8 rounded-lg flex items-center justify-center text-zinc-400 hover:bg-zinc-100 dark:hover:bg-zinc-800">
             <X size={16} />
           </button>
         </div>
@@ -102,7 +102,7 @@ export default function ContributorInviteDialog({ journeyId, existingUserIds, on
             <label className="text-[10px] font-semibold tracking-[0.12em] uppercase text-zinc-500 block mb-2">{t('journey.invite.role')}</label>
             <div className="flex gap-2">
               {(['viewer', 'editor'] as const).map(r => (
-                <button
+                <button type="button"
                   key={r}
                   onClick={() => setRole(r)}
                   className={`flex-1 py-2 rounded-lg text-[12px] font-medium border transition-all ${
@@ -119,10 +119,10 @@ export default function ContributorInviteDialog({ journeyId, existingUserIds, on
         </div>
 
         <div className="flex items-center justify-end gap-2 px-6 py-4 border-t border-zinc-200 dark:border-zinc-700 bg-zinc-50 dark:bg-zinc-800/50">
-          <button onClick={onClose} className="px-3.5 py-2 rounded-lg border border-zinc-200 dark:border-zinc-600 text-[13px] font-medium text-zinc-700 dark:text-zinc-300 hover:bg-zinc-100 dark:hover:bg-zinc-700">
+          <button type="button" onClick={onClose} className="px-3.5 py-2 rounded-lg border border-zinc-200 dark:border-zinc-600 text-[13px] font-medium text-zinc-700 dark:text-zinc-300 hover:bg-zinc-100 dark:hover:bg-zinc-700">
             {t('common.cancel')}
           </button>
-          <button
+          <button type="button"
             onClick={handleInvite}
             disabled={!selectedUserId || sending}
             className="px-3.5 py-2 rounded-lg bg-zinc-900 dark:bg-white text-white dark:text-zinc-900 text-[13px] font-medium hover:bg-zinc-800 dark:hover:bg-zinc-100 disabled:opacity-40 disabled:cursor-not-allowed"
diff --git a/client/src/components/Journey/JourneyDetailPageAddTripDialog.tsx b/client/src/components/Journey/JourneyDetailPageAddTripDialog.tsx
index 06db7f9b8..14f70c6b6 100644
--- a/client/src/components/Journey/JourneyDetailPageAddTripDialog.tsx
+++ b/client/src/components/Journey/JourneyDetailPageAddTripDialog.tsx
@@ -47,7 +47,7 @@ export function AddTripDialog({ journeyId, existingTripIds, onClose, onAdded }:
 
         <div className="flex items-center justify-between px-6 py-4 border-b border-zinc-200 dark:border-zinc-700">
           <h2 className="text-[16px] font-bold text-zinc-900 dark:text-white">{t('journey.trips.linkTrip')}</h2>
-          <button onClick={onClose} className="w-8 h-8 rounded-lg flex items-center justify-center text-zinc-400 hover:bg-zinc-100 dark:hover:bg-zinc-800">
+          <button type="button" onClick={onClose} className="w-8 h-8 rounded-lg flex items-center justify-center text-zinc-400 hover:bg-zinc-100 dark:hover:bg-zinc-800">
             <X size={16} />
           </button>
         </div>
@@ -81,7 +81,7 @@ export function AddTripDialog({ journeyId, existingTripIds, onClose, onAdded }:
                     </div>
                   )}
                 </div>
-                <button
+                <button type="button"
                   onClick={() => handleAdd(trip.id)}
                   disabled={adding === trip.id}
                   className="px-3 py-1.5 rounded-lg text-[11px] font-semibold bg-zinc-900 dark:bg-white text-white dark:text-zinc-900 hover:bg-zinc-700 dark:hover:bg-zinc-200 disabled:opacity-50"
diff --git a/client/src/components/Journey/JourneyDetailPageEntryCard.tsx b/client/src/components/Journey/JourneyDetailPageEntryCard.tsx
index 836ab4893..ec4dc0195 100644
--- a/client/src/components/Journey/JourneyDetailPageEntryCard.tsx
+++ b/client/src/components/Journey/JourneyDetailPageEntryCard.tsx
@@ -73,15 +73,15 @@ export function EntryCard({ entry, readOnly, onEdit, onDelete, onPhotoClick }: {
           {/* Menu top-right */}
           {!readOnly && (
             <div className="absolute top-2.5 right-3 z-[2]">
-              <button ref={menuBtnRef} onClick={() => setMenuOpen(!menuOpen)} className="w-8 h-8 rounded-[10px] bg-black/40 backdrop-blur-sm flex items-center justify-center text-white hover:bg-black/50">
+              <button type="button" ref={menuBtnRef} onClick={() => setMenuOpen(!menuOpen)} className="w-8 h-8 rounded-[10px] bg-black/40 backdrop-blur-sm flex items-center justify-center text-white hover:bg-black/50">
                 <MoreHorizontal size={14} />
               </button>
               {menuOpen && createPortal(
                 <>
                   <div className="fixed inset-0 z-[99]" onClick={() => setMenuOpen(false)} />
                   <div className="fixed z-[100] bg-white dark:bg-zinc-800 border border-zinc-200 dark:border-zinc-700 rounded-lg shadow-lg py-1 min-w-[120px]" style={{ top: (menuBtnRef.current?.getBoundingClientRect().bottom || 0) + 4, right: window.innerWidth - (menuBtnRef.current?.getBoundingClientRect().right || 0) }}>
-                    <button onClick={() => { setMenuOpen(false); onEdit() }} className="w-full text-left px-3 py-1.5 text-[12px] text-zinc-700 dark:text-zinc-300 hover:bg-zinc-50 dark:hover:bg-zinc-700 flex items-center gap-2"><Pencil size={12} /> {t('common.edit')}</button>
-                    <button onClick={() => { setMenuOpen(false); onDelete() }} className="w-full text-left px-3 py-1.5 text-[12px] text-red-600 dark:text-red-400 hover:bg-red-50 dark:hover:bg-red-900/20 flex items-center gap-2"><Trash2 size={12} /> {t('common.delete')}</button>
+                    <button type="button" onClick={() => { setMenuOpen(false); onEdit() }} className="w-full text-left px-3 py-1.5 text-[12px] text-zinc-700 dark:text-zinc-300 hover:bg-zinc-50 dark:hover:bg-zinc-700 flex items-center gap-2"><Pencil size={12} /> {t('common.edit')}</button>
+                    <button type="button" onClick={() => { setMenuOpen(false); onDelete() }} className="w-full text-left px-3 py-1.5 text-[12px] text-red-600 dark:text-red-400 hover:bg-red-50 dark:hover:bg-red-900/20 flex items-center gap-2"><Trash2 size={12} /> {t('common.delete')}</button>
                   </div>
                 </>,
                 document.body,
@@ -113,15 +113,15 @@ export function EntryCard({ entry, readOnly, onEdit, onDelete, onPhotoClick }: {
           </div>
           {!readOnly && (
             <div className="relative">
-              <button ref={menuBtnRef} onClick={() => setMenuOpen(!menuOpen)} className="w-7 h-7 rounded-md flex items-center justify-center text-zinc-400 hover:bg-zinc-100 dark:hover:bg-zinc-800">
+              <button type="button" ref={menuBtnRef} onClick={() => setMenuOpen(!menuOpen)} className="w-7 h-7 rounded-md flex items-center justify-center text-zinc-400 hover:bg-zinc-100 dark:hover:bg-zinc-800">
                 <MoreHorizontal size={14} />
               </button>
               {menuOpen && createPortal(
                 <>
                   <div className="fixed inset-0 z-[99]" onClick={() => setMenuOpen(false)} />
                   <div className="fixed z-[100] bg-white dark:bg-zinc-800 border border-zinc-200 dark:border-zinc-700 rounded-lg shadow-lg py-1 min-w-[120px]" style={{ top: (menuBtnRef.current?.getBoundingClientRect().bottom || 0) + 4, right: window.innerWidth - (menuBtnRef.current?.getBoundingClientRect().right || 0) }}>
-                    <button onClick={() => { setMenuOpen(false); onEdit() }} className="w-full text-left px-3 py-1.5 text-[12px] text-zinc-700 dark:text-zinc-300 hover:bg-zinc-50 dark:hover:bg-zinc-700 flex items-center gap-2"><Pencil size={12} /> {t('common.edit')}</button>
-                    <button onClick={() => { setMenuOpen(false); onDelete() }} className="w-full text-left px-3 py-1.5 text-[12px] text-red-600 dark:text-red-400 hover:bg-red-50 dark:hover:bg-red-900/20 flex items-center gap-2"><Trash2 size={12} /> {t('common.delete')}</button>
+                    <button type="button" onClick={() => { setMenuOpen(false); onEdit() }} className="w-full text-left px-3 py-1.5 text-[12px] text-zinc-700 dark:text-zinc-300 hover:bg-zinc-50 dark:hover:bg-zinc-700 flex items-center gap-2"><Pencil size={12} /> {t('common.edit')}</button>
+                    <button type="button" onClick={() => { setMenuOpen(false); onDelete() }} className="w-full text-left px-3 py-1.5 text-[12px] text-red-600 dark:text-red-400 hover:bg-red-50 dark:hover:bg-red-900/20 flex items-center gap-2"><Trash2 size={12} /> {t('common.delete')}</button>
                   </div>
                 </>,
                 document.body,
diff --git a/client/src/components/Journey/JourneyDetailPageEntryEditor.tsx b/client/src/components/Journey/JourneyDetailPageEntryEditor.tsx
index 0a8792ea6..6baaa6d65 100644
--- a/client/src/components/Journey/JourneyDetailPageEntryEditor.tsx
+++ b/client/src/components/Journey/JourneyDetailPageEntryEditor.tsx
@@ -209,7 +209,7 @@ export function EntryEditor({ entry, journeyId, tripDates, galleryPhotos, trips,
     setPendingFiles(prev => [...prev, ...normalized])
   }
 
-  const contextLocation = isValidGeoPoint({ lat: locationLat ?? NaN, lng: locationLng ?? NaN })
+  const contextLocation = isValidGeoPoint({ lat: locationLat ?? Number.NaN, lng: locationLng ?? Number.NaN })
     ? { lat: locationLat!, lng: locationLng!, name: locationName || undefined }
     : null
 
@@ -256,7 +256,7 @@ export function EntryEditor({ entry, journeyId, tripDates, galleryPhotos, trips,
 
         <div className="flex items-center justify-between px-6 py-4 border-b border-zinc-200 dark:border-zinc-700">
           <h2 className="text-[16px] font-bold text-zinc-900 dark:text-white">{entry.id === 0 ? t('journey.detail.newEntry') : t('journey.detail.editEntry')}</h2>
-          <button onClick={handleClose} className="w-8 h-8 rounded-full flex items-center justify-center text-zinc-400 hover:bg-zinc-100 dark:hover:bg-zinc-800">
+          <button type="button" onClick={handleClose} className="w-8 h-8 rounded-full flex items-center justify-center text-zinc-400 hover:bg-zinc-100 dark:hover:bg-zinc-800">
             <X size={16} />
           </button>
         </div>
@@ -275,7 +275,7 @@ export function EntryEditor({ entry, journeyId, tripDates, galleryPhotos, trips,
             <input ref={fileRef} type="file" accept="image/*" multiple onChange={handleFileChange} onClick={e => { (e.target as HTMLInputElement).value = '' }} className="hidden" />
             <input ref={cameraRef} type="file" accept="image/*" capture="environment" onChange={handleFileChange} onClick={e => { (e.target as HTMLInputElement).value = '' }} className="hidden" />
             <div className="flex gap-2">
-              <button
+              <button type="button"
                 onClick={() => { setPhotoTab('upload'); setShowGalleryPick(false); fileRef.current?.click() }}
                 disabled={saving}
                 className="flex-1 border border-dashed border-zinc-200 dark:border-zinc-700 rounded-xl py-4 text-[12px] text-zinc-500 hover:border-zinc-400 dark:hover:border-zinc-500 hover:bg-zinc-50 dark:hover:bg-zinc-800 flex items-center justify-center gap-1.5 disabled:opacity-50"
@@ -287,7 +287,7 @@ export function EntryEditor({ entry, journeyId, tripDates, galleryPhotos, trips,
                 )}
               </button>
               {galleryPhotos.length > 0 && (
-                <button
+                <button type="button"
                   onClick={() => { setPhotoTab('gallery'); setShowGalleryPick(!showGalleryPick) }}
                   className={`flex-1 border rounded-xl py-4 text-[12px] text-zinc-500 flex items-center justify-center gap-1.5 ${
                     showGalleryPick
@@ -298,7 +298,7 @@ export function EntryEditor({ entry, journeyId, tripDates, galleryPhotos, trips,
                   <Image size={13} /> {t('journey.editor.fromGallery')}
                 </button>
               )}
-              <button
+              <button type="button"
                 onClick={() => { setPhotoTab('upload'); setShowGalleryPick(false); cameraRef.current?.click() }}
                 disabled={saving}
                 aria-label={t('journey.photo.add')}
@@ -307,7 +307,7 @@ export function EntryEditor({ entry, journeyId, tripDates, galleryPhotos, trips,
               >
                 <Camera size={14} />
               </button>
-              <button
+              <button type="button"
                 onClick={() => { setPhotoTab('external'); setShowGalleryPick(false) }}
                 disabled={saving}
                 className={`flex-1 border rounded-lg py-4 text-[12px] text-zinc-500 flex items-center justify-center gap-1.5 ${
@@ -367,7 +367,7 @@ export function EntryEditor({ entry, journeyId, tripDates, galleryPhotos, trips,
                     </p>
                   </div>
                   {pendingProviderGroups.length > 0 && (
-                    <button onClick={() => setPendingProviderGroups([])} className="text-[10px] text-zinc-500 hover:text-zinc-900 dark:hover:text-white whitespace-nowrap">
+                    <button type="button" onClick={() => setPendingProviderGroups([])} className="text-[10px] text-zinc-500 hover:text-zinc-900 dark:hover:text-white whitespace-nowrap">
                       {pendingProviderGroups.reduce((sum, group) => sum + group.assetIds.length, 0)} {t('journey.editor.externalPhotosQueued') || 'queued'} · {t('common.clear') || 'Clear'}
                     </button>
                   )}
@@ -380,7 +380,7 @@ export function EntryEditor({ entry, journeyId, tripDates, galleryPhotos, trips,
                   <div className="h-full min-h-0 flex flex-col">
                     <div className="flex gap-1 px-3 py-2 border-b border-zinc-200 dark:border-zinc-700 overflow-x-auto">
                       {availableProviders.map(provider => (
-                        <button
+                        <button type="button"
                           key={provider.id}
                           data-testid={`journey-external-provider-${provider.id}`}
                           onClick={() => setExternalProvider(provider.id)}
@@ -442,7 +442,7 @@ export function EntryEditor({ entry, journeyId, tripDates, galleryPhotos, trips,
                         <span className="absolute bottom-0.5 left-0.5 px-1 py-px rounded text-[8px] font-bold bg-zinc-900/70 text-white">{t('journey.editor.photoFirst')}</span>
                       )}
                       {idx > 0 && photos.length > 1 && (
-                        <button
+                        <button type="button"
                           onClick={e => {
                             e.stopPropagation()
                             const prevOrder = photos
@@ -470,7 +470,7 @@ export function EntryEditor({ entry, journeyId, tripDates, galleryPhotos, trips,
                           {t('journey.editor.makeFirst')}
                         </button>
                       )}
-                      <button
+                      <button type="button"
                         onClick={async (e) => {
                           e.stopPropagation()
                           setPhotos(prev => prev.filter(x => x.id !== p.id))
@@ -490,7 +490,7 @@ export function EntryEditor({ entry, journeyId, tripDates, galleryPhotos, trips,
                   {pendingFiles.map((f, i) => (
                     <div key={`pending-${i}`} className="w-20 h-20 rounded-xl overflow-hidden relative group">
                       <img src={pendingUrls[i]} className="w-full h-full object-cover" alt="" />
-                      <button
+                      <button type="button"
                         onClick={() => setPendingFiles(prev => prev.filter((_, j) => j !== i))}
                         className="absolute top-1 right-1 w-5 h-5 rounded-full bg-black/60 text-white flex items-center justify-center opacity-0 group-hover:opacity-100 transition-opacity"
                       >
@@ -544,13 +544,13 @@ export function EntryEditor({ entry, journeyId, tripDates, galleryPhotos, trips,
                         className="flex-1 min-w-0 bg-transparent border-none outline-none text-[13px] text-zinc-900 dark:text-zinc-100 placeholder:text-green-400 dark:placeholder:text-green-600"
                       />
                       {pros.length > 1 && (
-                        <button onClick={() => setPros(pros.filter((_, j) => j !== i))} className="p-1 text-green-300 dark:text-green-700 hover:text-green-600 dark:hover:text-green-400 flex-shrink-0">
+                        <button type="button" onClick={() => setPros(pros.filter((_, j) => j !== i))} className="p-1 text-green-300 dark:text-green-700 hover:text-green-600 dark:hover:text-green-400 flex-shrink-0">
                           <X size={13} strokeWidth={2.5} />
                         </button>
                       )}
                     </div>
                   ))}
-                  <button
+                  <button type="button"
                     onClick={() => setPros([...pros, ''])}
                     className="flex items-center justify-center gap-1.5 h-9 w-full border border-dashed border-green-200 dark:border-green-800/40 rounded-[10px] text-[12px] font-medium text-green-700 dark:text-green-400 hover:border-green-300 dark:hover:border-green-700 transition-colors"
                   >
@@ -578,13 +578,13 @@ export function EntryEditor({ entry, journeyId, tripDates, galleryPhotos, trips,
                         className="flex-1 min-w-0 bg-transparent border-none outline-none text-[13px] text-zinc-900 dark:text-zinc-100 placeholder:text-red-400 dark:placeholder:text-red-600"
                       />
                       {cons.length > 1 && (
-                        <button onClick={() => setCons(cons.filter((_, j) => j !== i))} className="p-1 text-red-300 dark:text-red-700 hover:text-red-600 dark:hover:text-red-400 flex-shrink-0">
+                        <button type="button" onClick={() => setCons(cons.filter((_, j) => j !== i))} className="p-1 text-red-300 dark:text-red-700 hover:text-red-600 dark:hover:text-red-400 flex-shrink-0">
                           <X size={13} strokeWidth={2.5} />
                         </button>
                       )}
                     </div>
                   ))}
-                  <button
+                  <button type="button"
                     onClick={() => setCons([...cons, ''])}
                     className="flex items-center justify-center gap-1.5 h-9 w-full border border-dashed border-red-200 dark:border-red-800/40 rounded-[10px] text-[12px] font-medium text-red-700 dark:text-red-400 hover:border-red-300 dark:hover:border-red-700 transition-colors"
                   >
@@ -661,7 +661,7 @@ export function EntryEditor({ entry, journeyId, tripDates, galleryPhotos, trips,
                   <div className="fixed inset-0 z-[99]" onClick={() => setShowLocationResults(false)} />
                   <div className="absolute left-0 right-0 top-full mt-1 z-[100] bg-white dark:bg-zinc-800 border border-zinc-200 dark:border-zinc-700 rounded-xl shadow-lg overflow-hidden max-h-[240px] overflow-y-auto">
                     {locationResults.map((r, i) => (
-                      <button
+                      <button type="button"
                         key={i}
                         onClick={() => {
                           setLocationName(r.name)
@@ -698,7 +698,7 @@ export function EntryEditor({ entry, journeyId, tripDates, galleryPhotos, trips,
                 const Icon = config.icon
                 const active = mood === key
                 return (
-                  <button key={key} onClick={() => setMood(active ? '' : key)}
+                  <button type="button" key={key} onClick={() => setMood(active ? '' : key)}
                     className={`flex items-center gap-1.5 px-3 py-1.5 rounded-full text-[12px] font-semibold border transition-all ${
                       active ? '' : 'border-zinc-200 dark:border-zinc-700 text-zinc-500'
                     }`}
@@ -718,7 +718,7 @@ export function EntryEditor({ entry, journeyId, tripDates, galleryPhotos, trips,
                 const Icon = config.icon
                 const active = weather === key
                 return (
-                  <button key={key} onClick={() => setWeather(active ? '' : key)}
+                  <button type="button" key={key} onClick={() => setWeather(active ? '' : key)}
                     className={`flex items-center gap-1.5 px-3 py-1.5 rounded-full text-[12px] font-semibold border transition-all ${
                       active ? 'bg-zinc-900 dark:bg-white text-white dark:text-zinc-900 border-zinc-900 dark:border-white' : 'border-zinc-200 dark:border-zinc-700 text-zinc-500 hover:border-zinc-400'
                     }`}>
@@ -735,8 +735,8 @@ export function EntryEditor({ entry, journeyId, tripDates, galleryPhotos, trips,
 
 
         <div className="flex items-center justify-end gap-2 px-6 py-4 border-t border-zinc-200 dark:border-zinc-700 bg-zinc-50 dark:bg-zinc-800/50" style={{ paddingBottom: 'max(16px, env(safe-area-inset-bottom, 16px))' }}>
-          <button onClick={handleClose} className="px-4 h-10 flex items-center rounded-full border border-zinc-200 dark:border-zinc-600 text-[13px] font-semibold text-zinc-700 dark:text-zinc-300 hover:bg-zinc-100 dark:hover:bg-zinc-700 transition-colors">{t('common.cancel')}</button>
-          <button onClick={handleSave} disabled={saving} className="px-5 h-10 flex items-center rounded-full bg-zinc-900 dark:bg-white text-white dark:text-zinc-900 text-[13px] font-semibold hover:bg-zinc-800 dark:hover:bg-zinc-100 disabled:opacity-50 transition-colors">
+          <button type="button" onClick={handleClose} className="px-4 h-10 flex items-center rounded-full border border-zinc-200 dark:border-zinc-600 text-[13px] font-semibold text-zinc-700 dark:text-zinc-300 hover:bg-zinc-100 dark:hover:bg-zinc-700 transition-colors">{t('common.cancel')}</button>
+          <button type="button" onClick={handleSave} disabled={saving} className="px-5 h-10 flex items-center rounded-full bg-zinc-900 dark:bg-white text-white dark:text-zinc-900 text-[13px] font-semibold hover:bg-zinc-800 dark:hover:bg-zinc-100 disabled:opacity-50 transition-colors">
             {saving ? t('common.saving') : t('common.save')}
           </button>
         </div>
diff --git a/client/src/components/Journey/JourneyDetailPageExpandableStory.tsx b/client/src/components/Journey/JourneyDetailPageExpandableStory.tsx
index d26b53733..bb93db665 100644
--- a/client/src/components/Journey/JourneyDetailPageExpandableStory.tsx
+++ b/client/src/components/Journey/JourneyDetailPageExpandableStory.tsx
@@ -35,7 +35,7 @@ export function ExpandableStory({ story }: { story: string }) {
         <JournalBody text={story} />
       </div>
       {clamped && !expanded && (
-        <button
+        <button type="button"
           onClick={() => setExpanded(true)}
           className="mt-2 inline-flex items-center gap-1 px-2.5 py-1 rounded-full bg-zinc-100 dark:bg-zinc-800 text-[10px] font-medium text-zinc-500 dark:text-zinc-400 hover:bg-zinc-200 dark:hover:bg-zinc-700 active:scale-95 transition-all"
         >
@@ -43,7 +43,7 @@ export function ExpandableStory({ story }: { story: string }) {
         </button>
       )}
       {expanded && (
-        <button
+        <button type="button"
           onClick={() => setExpanded(false)}
           className="mt-2 inline-flex items-center gap-1 px-2.5 py-1 rounded-full bg-zinc-100 dark:bg-zinc-800 text-[10px] font-medium text-zinc-500 dark:text-zinc-400 hover:bg-zinc-200 dark:hover:bg-zinc-700 active:scale-95 transition-all"
         >
diff --git a/client/src/components/Journey/JourneyDetailPageGalleryView.tsx b/client/src/components/Journey/JourneyDetailPageGalleryView.tsx
index f4bf2cc52..18f16d075 100644
--- a/client/src/components/Journey/JourneyDetailPageGalleryView.tsx
+++ b/client/src/components/Journey/JourneyDetailPageGalleryView.tsx
@@ -133,7 +133,7 @@ export function GalleryView({ entries, gallery, journeyId, userId, trips, onPhot
         </span>
         <div className="flex items-center gap-2">
           {availableProviders.map(p => (
-            <button
+            <button type="button"
               key={p.id}
               onClick={() => browseProvider(p.id)}
               className="inline-flex items-center gap-1.5 px-2.5 py-1.5 rounded-lg border border-zinc-200 dark:border-zinc-700 text-[11px] font-medium text-zinc-600 dark:text-zinc-400 hover:bg-zinc-50 dark:hover:bg-zinc-800"
@@ -176,7 +176,7 @@ export function GalleryView({ entries, gallery, journeyId, userId, trips, onPhot
                 </div>
               )}
               {/* Delete button */}
-              <button
+              <button type="button"
                 onClick={(e) => { e.stopPropagation(); handleDeletePhoto(photo.id) }}
                 className="absolute top-1.5 right-1.5 w-6 h-6 rounded-full bg-black/60 backdrop-blur text-white flex items-center justify-center opacity-0 group-hover:opacity-100 transition-opacity z-10"
               >
diff --git a/client/src/components/Journey/JourneyDetailPageProviderPicker.tsx b/client/src/components/Journey/JourneyDetailPageProviderPicker.tsx
index 9e5c47ea0..4737c5776 100644
--- a/client/src/components/Journey/JourneyDetailPageProviderPicker.tsx
+++ b/client/src/components/Journey/JourneyDetailPageProviderPicker.tsx
@@ -160,7 +160,7 @@ export function ProviderPicker({ provider, userId, entries, trips, existingAsset
           <h2 className="text-[16px] font-bold text-zinc-900 dark:text-white">
             {provider === 'immich' ? 'Immich' : provider === 'synologyphotos' ? 'Synology Photos' : provider}
           </h2>
-          <button onClick={onClose} className="w-8 h-8 rounded-lg flex items-center justify-center text-zinc-400 hover:bg-zinc-100 dark:hover:bg-zinc-800">
+          <button type="button" onClick={onClose} className="w-8 h-8 rounded-lg flex items-center justify-center text-zinc-400 hover:bg-zinc-100 dark:hover:bg-zinc-800">
             <X size={16} />
           </button>
         </div>}
@@ -176,7 +176,7 @@ export function ProviderPicker({ provider, userId, entries, trips, existingAsset
               { id: 'all' as const, label: t('journey.picker.allPhotos'), short: t('common.all') },
               { id: 'album' as const, label: t('journey.picker.albums') },
             ].map(f => (
-              <button
+              <button type="button"
                 key={f.id}
                 onClick={() => setFilter(f.id)}
                 className={`px-3 py-1.5 rounded-lg text-[12px] font-medium transition-colors ${
@@ -233,7 +233,7 @@ export function ProviderPicker({ provider, userId, entries, trips, existingAsset
                 <div className="flex-1"><DatePicker value={customFrom} onChange={setCustomFrom} /></div>
                 <span className="text-zinc-400 text-[12px]">&mdash;</span>
                 <div className="flex-1"><DatePicker value={customTo} onChange={setCustomTo} /></div>
-                <button onClick={handleCustomSearch}
+                <button type="button" onClick={handleCustomSearch}
                   className="px-3 py-1.5 rounded-lg bg-zinc-900 dark:bg-white text-white dark:text-zinc-900 text-[12px] font-medium hover:bg-zinc-800 dark:hover:bg-zinc-100 flex-shrink-0">
                   {t('journey.picker.search')}
                 </button>
@@ -243,7 +243,7 @@ export function ProviderPicker({ provider, userId, entries, trips, existingAsset
             {filter === 'album' && (
               <div className="flex gap-2 overflow-x-auto flex-1">
                 {albums.map((a: any) => (
-                  <button
+                  <button type="button"
                     key={a.id}
                     onClick={() => { setSelectedAlbum(a.id); setSelectedAlbumPassphrase(a.passphrase); loadAlbumPhotos(a) }}
                     className={`px-2.5 py-1 rounded-lg text-[11px] font-medium whitespace-nowrap flex-shrink-0 border ${
@@ -265,7 +265,7 @@ export function ProviderPicker({ provider, userId, entries, trips, existingAsset
         {!embedded && <div className="px-6 py-2.5 border-b border-zinc-200 dark:border-zinc-700 bg-zinc-50 dark:bg-zinc-800/50 flex-shrink-0">
           <div className="relative flex items-center gap-2">
             <span className="text-[10px] font-semibold tracking-[0.12em] uppercase text-zinc-500">{t('journey.picker.addTo')}</span>
-            <button
+            <button type="button"
               onClick={() => setAddToOpen(!addToOpen)}
               className="flex items-center gap-1.5 px-3 py-1.5 rounded-lg border border-zinc-200 dark:border-zinc-700 text-[12px] font-medium text-zinc-700 dark:text-zinc-300 hover:bg-zinc-50 dark:hover:bg-zinc-800"
             >
@@ -276,7 +276,7 @@ export function ProviderPicker({ provider, userId, entries, trips, existingAsset
               <>
                 <div className="fixed inset-0 z-[9]" onClick={() => setAddToOpen(false)} />
                 <div className="absolute left-12 top-full mt-1 z-10 bg-white dark:bg-zinc-800 border border-zinc-200 dark:border-zinc-700 rounded-xl shadow-lg py-1.5 min-w-[200px] max-h-[240px] overflow-y-auto">
-                  <button
+                  <button type="button"
                     onClick={() => { setTargetEntryId(null); setAddToOpen(false) }}
                     className={`w-full text-left px-3 py-2 text-[12px] flex items-center gap-2 ${
                       !targetEntryId
@@ -291,7 +291,7 @@ export function ProviderPicker({ provider, userId, entries, trips, existingAsset
                     <div className="h-px bg-zinc-200 dark:bg-zinc-700 my-1" />
                   )}
                   {entries.filter(e => e.type !== 'skeleton' && e.title !== 'Gallery' && e.title !== '[Trip Photos]').map(e => (
-                    <button
+                    <button type="button"
                       key={e.id}
                       onClick={() => { setTargetEntryId(e.id); setAddToOpen(false) }}
                       className={`w-full text-left px-3 py-2 text-[12px] truncate ${
@@ -316,7 +316,7 @@ export function ProviderPicker({ provider, userId, entries, trips, existingAsset
           if (selectable.length === 0) return null
           return (
             <div className="px-4 py-2 border-b border-zinc-200 dark:border-zinc-700 bg-white dark:bg-zinc-900 flex-shrink-0">
-              <button
+              <button type="button"
                 onClick={() => {
                   if (allSelected) {
                     setSelected(new Map())
@@ -421,10 +421,10 @@ export function ProviderPicker({ provider, userId, entries, trips, existingAsset
             <span className="leading-[18px]">{t('journey.picker.selected')}</span>
           </span>
           <div className="flex items-center gap-2">
-            <button onClick={onClose} className="px-3.5 py-2 rounded-lg border border-zinc-200 dark:border-zinc-600 text-[13px] font-medium text-zinc-700 dark:text-zinc-300 hover:bg-zinc-100 dark:hover:bg-zinc-700">
+            <button type="button" onClick={onClose} className="px-3.5 py-2 rounded-lg border border-zinc-200 dark:border-zinc-600 text-[13px] font-medium text-zinc-700 dark:text-zinc-300 hover:bg-zinc-100 dark:hover:bg-zinc-700">
               {t('common.cancel')}
             </button>
-            <button
+            <button type="button"
               onClick={() => {
                 const groupMap = new Map<string | undefined, { assetIds: string[]; mediaTypes: string[] }>()
                 for (const [assetId, { passphrase, mediaType }] of selected.entries()) {
diff --git a/client/src/components/Journey/JourneyDetailPageSettingsDialog.tsx b/client/src/components/Journey/JourneyDetailPageSettingsDialog.tsx
index c79772298..a461916fa 100644
--- a/client/src/components/Journey/JourneyDetailPageSettingsDialog.tsx
+++ b/client/src/components/Journey/JourneyDetailPageSettingsDialog.tsx
@@ -92,7 +92,7 @@ export function JourneySettingsDialog({ journey, onClose, onSaved, onOpenInvite,
 
         <div className="flex items-center justify-between px-6 py-4 border-b border-zinc-200 dark:border-zinc-700">
           <h2 className="text-[16px] font-bold text-zinc-900 dark:text-white">{t('journey.settings.title')}</h2>
-          <button onClick={handleClose} className="w-8 h-8 rounded-xl flex items-center justify-center text-zinc-400 hover:bg-zinc-100 dark:hover:bg-zinc-800">
+          <button type="button" onClick={handleClose} className="w-8 h-8 rounded-xl flex items-center justify-center text-zinc-400 hover:bg-zinc-100 dark:hover:bg-zinc-800">
             <X size={16} />
           </button>
         </div>
@@ -105,7 +105,7 @@ export function JourneySettingsDialog({ journey, onClose, onSaved, onOpenInvite,
           <div>
             <label className="text-[10px] font-semibold tracking-[0.12em] uppercase text-zinc-500 block mb-2">{t('journey.settings.coverImage')}</label>
             <input ref={coverRef} type="file" accept="image/*" onChange={handleCoverUpload} className="hidden" />
-            <button
+            <button type="button"
               onClick={() => coverRef.current?.click()}
               className="w-full h-28 rounded-xl border border-dashed border-zinc-200 dark:border-zinc-700 flex items-center justify-center gap-2 text-[12px] text-zinc-500 hover:border-zinc-400 dark:hover:border-zinc-500 hover:bg-zinc-50 dark:hover:bg-zinc-800 overflow-hidden relative"
             >
@@ -156,7 +156,7 @@ export function JourneySettingsDialog({ journey, onClose, onSaved, onOpenInvite,
                     <div className="text-[12px] font-medium text-zinc-900 dark:text-white">{trip.title}</div>
                     <div className="text-[10px] text-zinc-500">{trip.place_count || 0} {t('journey.synced.places')}</div>
                   </div>
-                  <button
+                  <button type="button"
                     onClick={() => setUnlinkTarget({ trip_id: trip.trip_id, title: trip.title })}
                     className="w-8 h-8 rounded-xl flex-shrink-0 flex items-center justify-center bg-red-500/10 text-red-500 hover:bg-red-500/20 dark:bg-red-500/15 dark:hover:bg-red-500/25 transition-colors"
                     title="Unlink trip"
@@ -166,7 +166,7 @@ export function JourneySettingsDialog({ journey, onClose, onSaved, onOpenInvite,
                 </div>
               ))}
               {journey.trips.length === 0 && <p className="text-[11px] text-zinc-400">{t('journey.trips.noTripsLinkedSettings')}</p>}
-              <button
+              <button type="button"
                 onClick={() => setShowAddTrip(true)}
                 className="w-full mt-1 flex items-center justify-center gap-1.5 py-2.5 rounded-xl border border-dashed border-zinc-300 dark:border-zinc-600 text-[12px] font-medium text-zinc-500 hover:border-zinc-400 hover:text-zinc-700 dark:hover:border-zinc-500 dark:hover:text-zinc-300 transition-colors"
               >
@@ -187,7 +187,7 @@ export function JourneySettingsDialog({ journey, onClose, onSaved, onOpenInvite,
                   <div className="flex-1 text-[12px] font-medium text-zinc-900 dark:text-white">{c.username}</div>
                   <span className="shrink-0 rounded-full font-semibold uppercase" style={{ fontSize: 8.5, letterSpacing: '0.05em', padding: '2px 7px', ...(c.role === 'owner' ? { background: 'var(--vg-ink)', color: 'var(--vg-bg)' } : { background: 'color-mix(in srgb, var(--vg-ink3) 14%, transparent)', color: 'var(--vg-ink2)' }) }}>{c.role}</span>
                   {c.role !== 'owner' && (
-                    <button
+                    <button type="button"
                       onClick={async () => {
                         if (!window.confirm(t('journey.contributors.removeConfirm', { username: c.username }))) return
                         try {
@@ -207,7 +207,7 @@ export function JourneySettingsDialog({ journey, onClose, onSaved, onOpenInvite,
                   )}
                 </div>
               ))}
-              <button
+              <button type="button"
                 onClick={onOpenInvite}
                 className="w-full mt-1 flex items-center justify-center gap-1.5 py-2.5 rounded-xl border border-dashed border-zinc-300 dark:border-zinc-600 text-[12px] font-medium text-zinc-500 hover:border-zinc-400 hover:text-zinc-700 dark:hover:border-zinc-500 dark:hover:text-zinc-300 transition-colors"
               >
@@ -228,7 +228,7 @@ export function JourneySettingsDialog({ journey, onClose, onSaved, onOpenInvite,
 
         {/* Footer */}
         <div className="flex items-center gap-1.5 px-4 md:px-6 py-4 pb-6 md:pb-4 border-t border-zinc-200 dark:border-zinc-700 bg-zinc-50 dark:bg-zinc-800/50">
-          <button
+          <button type="button"
             onClick={() => setShowDeleteConfirm(true)}
             aria-label={t('journey.settings.delete')}
             title={t('journey.settings.delete')}
@@ -237,7 +237,7 @@ export function JourneySettingsDialog({ journey, onClose, onSaved, onOpenInvite,
             <Trash2 size={14} />
             <span className="hidden md:inline">{t('journey.settings.delete')}</span>
           </button>
-          <button
+          <button type="button"
             onClick={handleArchiveToggle}
             disabled={archiving}
             aria-label={journey.status === 'archived' ? t('journey.settings.reopenJourney') : t('journey.settings.endJourney')}
@@ -247,8 +247,8 @@ export function JourneySettingsDialog({ journey, onClose, onSaved, onOpenInvite,
             {journey.status === 'archived' ? <ArchiveRestore size={14} /> : <Archive size={14} />}
             <span className="hidden md:inline">{journey.status === 'archived' ? t('journey.settings.reopenJourney') : t('journey.settings.endJourney')}</span>
           </button>
-          <button onClick={handleClose} className="h-10 px-4 rounded-full border border-zinc-200 dark:border-zinc-600 text-[13px] font-semibold text-zinc-700 dark:text-zinc-300 hover:bg-zinc-100 dark:hover:bg-zinc-700 transition-colors">{t('common.cancel')}</button>
-          <button onClick={handleSave} disabled={saving || !title.trim()} className="h-10 px-5 rounded-full bg-zinc-900 dark:bg-white text-white dark:text-zinc-900 text-[13px] font-semibold hover:bg-zinc-800 dark:hover:bg-zinc-100 disabled:opacity-40 transition-colors">
+          <button type="button" onClick={handleClose} className="h-10 px-4 rounded-full border border-zinc-200 dark:border-zinc-600 text-[13px] font-semibold text-zinc-700 dark:text-zinc-300 hover:bg-zinc-100 dark:hover:bg-zinc-700 transition-colors">{t('common.cancel')}</button>
+          <button type="button" onClick={handleSave} disabled={saving || !title.trim()} className="h-10 px-5 rounded-full bg-zinc-900 dark:bg-white text-white dark:text-zinc-900 text-[13px] font-semibold hover:bg-zinc-800 dark:hover:bg-zinc-100 disabled:opacity-40 transition-colors">
             {saving ? t('common.saving') : t('common.save')}
           </button>
         </div>
diff --git a/client/src/components/Journey/JourneyDetailPageVerdictSection.tsx b/client/src/components/Journey/JourneyDetailPageVerdictSection.tsx
index 23fb3141b..f7ea2794a 100644
--- a/client/src/components/Journey/JourneyDetailPageVerdictSection.tsx
+++ b/client/src/components/Journey/JourneyDetailPageVerdictSection.tsx
@@ -9,7 +9,7 @@ export function VerdictSection({ pros, cons }: { pros: string[]; cons: string[]
   return (
     <div className="mt-5">
       {/* Header — clickable on mobile */}
-      <button
+      <button type="button"
         onClick={() => setOpen(o => !o)}
         className="md:pointer-events-none w-full flex items-center gap-2.5 mb-3.5 group"
       >
diff --git a/client/src/components/Journey/JourneyMap.tsx b/client/src/components/Journey/JourneyMap.tsx
index 0d0b421b4..5e5e3f89a 100644
--- a/client/src/components/Journey/JourneyMap.tsx
+++ b/client/src/components/Journey/JourneyMap.tsx
@@ -410,7 +410,7 @@ function JourneyMap(
         style={{ width: '100%', height: '100%' }}
       />
       <div style={{ position: 'absolute', bottom: 12, right: 12, zIndex: 400, display: 'flex', flexDirection: 'column', gap: 4 }}>
-        <button
+        <button type="button"
           onClick={zoomIn}
           style={{
             width: 32, height: 32, borderRadius: 8,
@@ -422,7 +422,7 @@ function JourneyMap(
             cursor: 'pointer', fontSize: 'calc(16px * var(--fs-scale-subtitle, 1))', fontWeight: 700, lineHeight: 1,
           }}
         >+</button>
-        <button
+        <button type="button"
           onClick={zoomOut}
           style={{
             width: 32, height: 32, borderRadius: 8,
diff --git a/client/src/components/Journey/JourneyShareSection.tsx b/client/src/components/Journey/JourneyShareSection.tsx
index d12ad9f2b..b574be460 100644
--- a/client/src/components/Journey/JourneyShareSection.tsx
+++ b/client/src/components/Journey/JourneyShareSection.tsx
@@ -66,7 +66,7 @@ export default function JourneyShareSection({ journeyId }: { journeyId: number }
       <label className="text-[10px] font-semibold tracking-[0.12em] uppercase text-zinc-500 block mb-2">{t('journey.share.publicShare')}</label>
 
       {!link ? (
-        <button
+        <button type="button"
           onClick={createLink}
           className="w-full flex items-center justify-center gap-1.5 py-2.5 rounded-xl border border-dashed border-zinc-300 dark:border-zinc-600 text-[12px] font-medium text-zinc-500 hover:border-zinc-400 hover:text-zinc-700 dark:hover:border-zinc-500 dark:hover:text-zinc-300 transition-colors"
         >
@@ -78,13 +78,13 @@ export default function JourneyShareSection({ journeyId }: { journeyId: number }
           <div className="flex items-center gap-2 p-2 rounded-2xl bg-zinc-50 dark:bg-zinc-800 border border-zinc-200 dark:border-zinc-700">
             <Link size={13} className="text-zinc-400 flex-shrink-0 ml-1.5" />
             <span className="flex-1 text-[11px] text-zinc-600 dark:text-zinc-400 truncate">{shareUrl}</span>
-            <button
+            <button type="button"
               onClick={copyLink}
               className="flex-shrink-0 px-3 py-1.5 rounded-full bg-zinc-900 dark:bg-white text-white dark:text-zinc-900 text-[11px] font-semibold hover:bg-zinc-700 dark:hover:bg-zinc-200 transition-colors"
             >
               {copied ? t('journey.share.copied') : t('journey.share.copy')}
             </button>
-            <button
+            <button type="button"
               onClick={deleteLink}
               className="flex-shrink-0 px-3 py-1.5 rounded-full text-[11px] font-semibold text-red-600 dark:text-red-400 hover:bg-red-50 dark:hover:bg-red-900/20 transition-colors"
             >
@@ -99,7 +99,7 @@ export default function JourneyShareSection({ journeyId }: { journeyId: number }
               { key: 'share_gallery' as const, label: t('journey.share.gallery'), icon: Grid },
               { key: 'share_map' as const, label: t('journey.share.map'), icon: MapPin },
             ].map(({ key, label, icon: Icon }) => (
-              <button
+              <button type="button"
                 key={key}
                 onClick={() => togglePerm(key)}
                 className={`flex items-center gap-2.5 px-3 py-2 rounded-xl border text-[12px] font-medium transition-all ${
diff --git a/client/src/components/Journey/MobileEntryCard.tsx b/client/src/components/Journey/MobileEntryCard.tsx
index 1146bad9f..da35d65de 100644
--- a/client/src/components/Journey/MobileEntryCard.tsx
+++ b/client/src/components/Journey/MobileEntryCard.tsx
@@ -72,7 +72,7 @@ export default function MobileEntryCard({ entry, dayLabel, dayColor, isActive, o
   const storyPreview = entry.story ? stripMarkdown(entry.story) : ''
 
   return (
-    <button
+    <button type="button"
       onClick={onClick}
       className={`flex-shrink-0 rounded-xl overflow-hidden text-left transition-all duration-100 ${
         isActive
diff --git a/client/src/components/Journey/MobileEntryView.tsx b/client/src/components/Journey/MobileEntryView.tsx
index 08c8dcdc7..5daf4d664 100644
--- a/client/src/components/Journey/MobileEntryView.tsx
+++ b/client/src/components/Journey/MobileEntryView.tsx
@@ -60,7 +60,7 @@ export default function MobileEntryView({ entry, readOnly, publicPhotoUrl, onClo
     <div className="fixed inset-0 z-[9999] bg-white dark:bg-zinc-950 flex flex-col overflow-hidden" style={{ height: '100dvh' }}>
       {/* Top bar */}
       <div className="flex items-center justify-between px-4 py-3 border-b border-zinc-100 dark:border-zinc-800 flex-shrink-0">
-        <button
+        <button type="button"
           onClick={onClose}
           className="w-9 h-9 rounded-lg flex items-center justify-center text-zinc-500 hover:bg-zinc-100 dark:hover:bg-zinc-800 transition-colors"
         >
@@ -68,14 +68,14 @@ export default function MobileEntryView({ entry, readOnly, publicPhotoUrl, onClo
         </button>
         {!readOnly && (
           <div className="flex items-center gap-1.5">
-            <button
+            <button type="button"
               onClick={() => { onClose(); onEdit(); }}
               className="h-8 px-3 rounded-lg bg-zinc-100 dark:bg-zinc-800 text-zinc-700 dark:text-zinc-300 text-[12px] font-medium flex items-center gap-1.5 hover:bg-zinc-200 dark:hover:bg-zinc-700 transition-colors"
             >
               <Pencil size={13} />
               {t('common.edit')}
             </button>
-            <button
+            <button type="button"
               onClick={() => { onClose(); onDelete(); }}
               className="w-8 h-8 rounded-lg flex items-center justify-center text-zinc-400 hover:bg-red-50 hover:text-red-500 dark:hover:bg-red-900/20 dark:hover:text-red-400 transition-colors"
             >
diff --git a/client/src/components/Journey/MobileMapTimeline.tsx b/client/src/components/Journey/MobileMapTimeline.tsx
index d7d43378d..84326088f 100644
--- a/client/src/components/Journey/MobileMapTimeline.tsx
+++ b/client/src/components/Journey/MobileMapTimeline.tsx
@@ -171,7 +171,7 @@ export default function MobileMapTimeline({
         />
         {!readOnly && onAddEntry && (
           <div className="fixed right-4 z-30" style={{ bottom: 'calc(var(--bottom-nav-h, 84px) + 16px)' }}>
-            <button
+            <button type="button"
               onClick={onAddEntry}
               className="w-12 h-12 rounded-full bg-zinc-900 dark:bg-white text-white dark:text-zinc-900 shadow-lg flex items-center justify-center hover:scale-105 active:scale-95 transition-transform"
             >
@@ -244,7 +244,7 @@ export default function MobileMapTimeline({
           className="fixed right-4 z-30"
           style={{ bottom: 'calc(var(--bottom-nav-h, 84px) + 168px)' }}
         >
-          <button
+          <button type="button"
             onClick={onAddEntry}
             className="w-12 h-12 rounded-full bg-zinc-900 dark:bg-white text-white dark:text-zinc-900 shadow-lg flex items-center justify-center hover:scale-105 active:scale-95 transition-transform"
           >
diff --git a/client/src/components/Journey/PhotoLightbox.tsx b/client/src/components/Journey/PhotoLightbox.tsx
index 64f9202c6..f8919552d 100644
--- a/client/src/components/Journey/PhotoLightbox.tsx
+++ b/client/src/components/Journey/PhotoLightbox.tsx
@@ -86,7 +86,7 @@ export default function PhotoLightbox({ photos, startIndex = 0, onClose }: Props
           <span style={{ color: 'rgba(255,255,255,0.5)', fontSize: 'calc(13px * var(--fs-scale-body, 1))', fontWeight: 500 }}>
             {idx + 1} / {photos.length}
           </span>
-          <button onClick={onClose} style={{
+          <button type="button" onClick={onClose} style={{
             background: 'rgba(255,255,255,0.1)', border: 'none', borderRadius: '50%',
             width: 36, height: 36, display: 'flex', alignItems: 'center', justifyContent: 'center',
             color: '#fff', cursor: 'pointer',
@@ -97,7 +97,7 @@ export default function PhotoLightbox({ photos, startIndex = 0, onClose }: Props
 
         {/* Prev button — visible on hover (desktop), always visible (mobile) */}
         {hasPrev && (
-          <button onClick={prev} className="flex sm:opacity-0 sm:group-hover/lightbox:opacity-100 transition-opacity" style={{
+          <button type="button" onClick={prev} className="flex sm:opacity-0 sm:group-hover/lightbox:opacity-100 transition-opacity" style={{
             position: 'absolute', left: 16, zIndex: 5,
             width: 44, height: 44, borderRadius: '50%',
             background: 'rgba(0,0,0,0.4)', backdropFilter: 'blur(8px)',
@@ -127,7 +127,7 @@ export default function PhotoLightbox({ photos, startIndex = 0, onClose }: Props
 
         {/* Next button */}
         {hasNext && (
-          <button onClick={next} className="flex sm:opacity-0 sm:group-hover/lightbox:opacity-100 transition-opacity" style={{
+          <button type="button" onClick={next} className="flex sm:opacity-0 sm:group-hover/lightbox:opacity-100 transition-opacity" style={{
             position: 'absolute', right: 16, zIndex: 5,
             width: 44, height: 44, borderRadius: '50%',
             background: 'rgba(0,0,0,0.4)', backdropFilter: 'blur(8px)',
diff --git a/client/src/components/Layout/BottomNav.tsx b/client/src/components/Layout/BottomNav.tsx
index 67ed52736..2946d8cf3 100644
--- a/client/src/components/Layout/BottomNav.tsx
+++ b/client/src/components/Layout/BottomNav.tsx
@@ -84,7 +84,7 @@ export default function BottomNav() {
   const renderItem = ({ to, label, icon: Icon }: NavItem) => {
     const active = isActive(to)
     return (
-      <button
+      <button type="button"
         key={to}
         onClick={() => navigate(to)}
         className="flex flex-col items-center gap-1 py-1 px-1 min-w-0"
@@ -115,7 +115,7 @@ export default function BottomNav() {
     >
       <div className="flex flex-1 items-center justify-around min-w-0">{left.map(renderItem)}</div>
 
-      <button
+      <button type="button"
         onClick={create.run}
         aria-label={create.label}
         className="flex items-center justify-center flex-shrink-0 active:scale-95 transition-transform"
diff --git a/client/src/components/Layout/DemoBanner.tsx b/client/src/components/Layout/DemoBanner.tsx
index a43feb7d0..a8179fefc 100644
--- a/client/src/components/Layout/DemoBanner.tsx
+++ b/client/src/components/Layout/DemoBanner.tsx
@@ -547,7 +547,7 @@ export default function DemoBanner(): React.ReactElement | null {
               {t.selfHostLink}
             </a>
           </div>
-          <button
+          <button type="button"
             onClick={() => setDismissed(true)}
             style={{
               background: '#111827',
diff --git a/client/src/components/Layout/InAppNotificationBell.tsx b/client/src/components/Layout/InAppNotificationBell.tsx
index ffabc2057..719aca9d2 100644
--- a/client/src/components/Layout/InAppNotificationBell.tsx
+++ b/client/src/components/Layout/InAppNotificationBell.tsx
@@ -42,7 +42,7 @@ export default function InAppNotificationBell(): React.ReactElement {
 
   return (
     <div className="relative flex-shrink-0">
-      <button
+      <button type="button"
         onClick={handleOpen}
         title={t('notifications.title')}
         className="relative p-2 rounded-lg transition-colors text-content-muted"
@@ -98,7 +98,7 @@ export default function InAppNotificationBell(): React.ReactElement {
               </span>
               <div className="flex items-center gap-1">
                 {unreadCount > 0 && (
-                  <button
+                  <button type="button"
                     onClick={markAllRead}
                     title={t('notifications.markAllRead')}
                     className="p-1.5 rounded-lg transition-colors text-content-muted"
@@ -109,7 +109,7 @@ export default function InAppNotificationBell(): React.ReactElement {
                   </button>
                 )}
                 {notifications.length > 0 && (
-                  <button
+                  <button type="button"
                     onClick={deleteAll}
                     title={t('notifications.deleteAll')}
                     className="p-1.5 rounded-lg transition-colors text-content-muted"
@@ -142,7 +142,7 @@ export default function InAppNotificationBell(): React.ReactElement {
             </div>
 
             {/* Footer */}
-            <button
+            <button type="button"
               onClick={handleShowAll}
               className="w-full py-2.5 text-xs font-medium transition-colors flex-shrink-0 border-t border-edge-secondary text-content"
               style={{
diff --git a/client/src/components/Layout/MobileTopBar.tsx b/client/src/components/Layout/MobileTopBar.tsx
index 4c8851974..88272948f 100644
--- a/client/src/components/Layout/MobileTopBar.tsx
+++ b/client/src/components/Layout/MobileTopBar.tsx
@@ -24,7 +24,7 @@ export default function MobileTopBar() {
         className="md:hidden flex items-center justify-end gap-2 px-4"
         style={{ paddingTop: 'calc(10px + env(safe-area-inset-top, 0px))', paddingBottom: 10 }}
       >
-        <button
+        <button type="button"
           onClick={() => navigate('/notifications')}
           aria-label={t('notifications.title')}
           className="relative grid place-items-center rounded-full active:scale-95 transition-transform"
@@ -35,7 +35,7 @@ export default function MobileTopBar() {
             <span style={{ position: 'absolute', top: 7, right: 7, width: 8, height: 8, borderRadius: '50%', background: 'oklch(0.7 0.17 38)', boxShadow: '0 0 0 2px var(--bg, #fff)' }} />
           )}
         </button>
-        <button
+        <button type="button"
           onClick={() => setShowProfile(true)}
           aria-label={t('nav.profile')}
           className="grid place-items-center rounded-full text-white font-semibold text-[12px] active:scale-95 transition-transform"
@@ -90,7 +90,7 @@ function ProfileSheet({ onClose }: { onClose: () => void }) {
         <div className="h-px bg-zinc-100 dark:bg-zinc-800 mx-4" />
 
         <div className="py-2 px-2">
-          <button
+          <button type="button"
             onClick={() => handleNav('/settings')}
             className="w-full flex items-center gap-3 px-4 py-3 rounded-xl text-left hover:bg-zinc-50 dark:hover:bg-zinc-800 active:bg-zinc-100 dark:active:bg-zinc-800 transition-colors"
           >
@@ -99,7 +99,7 @@ function ProfileSheet({ onClose }: { onClose: () => void }) {
           </button>
 
           {user?.role === 'admin' && (
-            <button
+            <button type="button"
               onClick={() => handleNav('/admin')}
               className="w-full flex items-center gap-3 px-4 py-3 rounded-xl text-left hover:bg-zinc-50 dark:hover:bg-zinc-800 active:bg-zinc-100 dark:active:bg-zinc-800 transition-colors"
             >
@@ -112,7 +112,7 @@ function ProfileSheet({ onClose }: { onClose: () => void }) {
         <div className="h-px bg-zinc-100 dark:bg-zinc-800 mx-4" />
 
         <div className="py-2 px-2">
-          <button
+          <button type="button"
             onClick={handleLogout}
             className="w-full flex items-center gap-3 px-4 py-3 rounded-xl text-left hover:bg-red-50 dark:hover:bg-red-900/20 active:bg-red-100 transition-colors"
           >
diff --git a/client/src/components/Layout/Navbar.tsx b/client/src/components/Layout/Navbar.tsx
index fffe57e90..48c6ed51d 100644
--- a/client/src/components/Layout/Navbar.tsx
+++ b/client/src/components/Layout/Navbar.tsx
@@ -115,7 +115,7 @@ export default function Navbar({ tripTitle, tripId, onBack, showBack, onShare }:
           being centred on top of both (#1983). */}
       <div className="flex items-center gap-3 min-w-0 flex-1 basis-0">
         {showBack && (
-          <button onClick={onBack}
+          <button type="button" onClick={onBack}
             className="trek-back-btn p-1.5 rounded-lg transition-colors flex items-center gap-1.5 text-sm flex-shrink-0 text-content-muted"
             onMouseEnter={e => e.currentTarget.style.background = 'var(--bg-hover)'}
             onMouseLeave={e => e.currentTarget.style.background = 'transparent'}>
@@ -215,7 +215,7 @@ export default function Navbar({ tripTitle, tripId, onBack, showBack, onShare }:
 
       {/* Share button */}
       {onShare && (
-        <button onClick={onShare}
+        <button type="button" onClick={onShare}
           className="flex items-center gap-1.5 py-1.5 px-3 rounded-lg border transition-colors text-sm font-medium flex-shrink-0 border-edge text-content-secondary bg-surface-card"
           onMouseEnter={e => e.currentTarget.style.background = 'var(--bg-hover)'}
           onMouseLeave={e => e.currentTarget.style.background = 'var(--bg-card)'}>
@@ -235,7 +235,7 @@ export default function Navbar({ tripTitle, tripId, onBack, showBack, onShare }:
       )}
 
       {/* Dark mode toggle (light ↔ dark, overrides auto) — hidden on mobile */}
-      <button onClick={toggleDarkMode} title={dark ? t('nav.lightMode') : t('nav.darkMode')}
+      <button type="button" onClick={toggleDarkMode} title={dark ? t('nav.lightMode') : t('nav.darkMode')}
         className="p-2 rounded-lg transition-colors flex-shrink-0 hidden sm:flex relative w-8 h-8 items-center justify-center text-content-muted"
         onMouseEnter={e => e.currentTarget.style.background = 'var(--bg-hover)'}
         onMouseLeave={e => e.currentTarget.style.background = 'transparent'}>
@@ -252,7 +252,7 @@ export default function Navbar({ tripTitle, tripId, onBack, showBack, onShare }:
       {/* User menu */}
       {user && (
         <div className="relative">
-          <button onClick={() => setUserMenuOpen(!userMenuOpen)}
+          <button type="button" onClick={() => setUserMenuOpen(!userMenuOpen)}
             className="flex items-center gap-2 py-1.5 px-3 rounded-lg transition-colors"
             onMouseEnter={e => e.currentTarget.style.background = 'var(--bg-hover)'}
             onMouseLeave={e => e.currentTarget.style.background = 'transparent'}>
@@ -313,7 +313,7 @@ export default function Navbar({ tripTitle, tripId, onBack, showBack, onShare }:
                 </div>
 
                 <div className="py-1 border-t border-edge-secondary">
-                  <button onClick={handleLogout}
+                  <button type="button" onClick={handleLogout}
                     className="flex items-center gap-2 w-full px-4 py-2 text-sm text-red-500 hover:bg-red-500/10 transition-colors">
                     <LogOut className="w-4 h-4" />
                     {t('nav.logout')}
diff --git a/client/src/components/Layout/PageSidebar.tsx b/client/src/components/Layout/PageSidebar.tsx
index d0f06a3bc..ad2841855 100644
--- a/client/src/components/Layout/PageSidebar.tsx
+++ b/client/src/components/Layout/PageSidebar.tsx
@@ -59,7 +59,7 @@ export default function PageSidebar({
       <div
         className="lg:hidden flex items-center justify-between px-4 py-3 border-b border-edge"
       >
-        <button
+        <button type="button"
           onClick={() => setMobileOpen(true)}
           className="w-9 h-9 rounded-lg flex items-center justify-center transition-colors hover:bg-[var(--bg-hover)] text-content"
           aria-label="Open navigation"
@@ -110,7 +110,7 @@ export default function PageSidebar({
               >
                 {sidebarLabel}
               </span>
-              <button
+              <button type="button"
                 onClick={() => setMobileOpen(false)}
                 className="w-8 h-8 rounded-lg flex items-center justify-center transition-colors hover:bg-[var(--bg-hover)] text-content"
                 aria-label="Close navigation"
@@ -177,7 +177,7 @@ function SidebarInner({
                     {tab.group}
                   </div>
                 )}
-                <button
+                <button type="button"
                   onClick={() => onTabChange(tab.id)}
                   className={`flex items-center gap-2.5 px-3 py-2 rounded-lg text-sm text-left transition-colors ${active ? 'text-content font-semibold' : 'text-content-secondary font-medium'}`}
                   style={{
diff --git a/client/src/components/Map/ReservationOverlay.tsx b/client/src/components/Map/ReservationOverlay.tsx
index ac9daeccf..aba5513e3 100644
--- a/client/src/components/Map/ReservationOverlay.tsx
+++ b/client/src/components/Map/ReservationOverlay.tsx
@@ -85,7 +85,7 @@ function parseInTz(isoLocal: string, tz: string): number {
   // minutes) makes Date.UTC NaN; bail before formatToParts, which throws on a
   // non-finite date and would blank the whole trip. computeDuration's finiteness
   // check then drops the duration cleanly.
-  if (!Number.isFinite(guess)) return NaN
+  if (!Number.isFinite(guess)) return Number.NaN
   const fmt = new Intl.DateTimeFormat('en-US', {
     timeZone: tz, hour12: false,
     year: 'numeric', month: '2-digit', day: '2-digit',
diff --git a/client/src/components/Map/reservationsMapbox.ts b/client/src/components/Map/reservationsMapbox.ts
index 63af95c59..58d89ad7f 100644
--- a/client/src/components/Map/reservationsMapbox.ts
+++ b/client/src/components/Map/reservationsMapbox.ts
@@ -57,7 +57,7 @@ function parseInTz(isoLocal: string, tz: string): number {
   // minutes) makes Date.UTC NaN; bail before formatToParts, which throws on a
   // non-finite date and would blank the whole trip. computeDuration's finiteness
   // check then drops the duration cleanly.
-  if (!Number.isFinite(guess)) return NaN
+  if (!Number.isFinite(guess)) return Number.NaN
   const fmt = new Intl.DateTimeFormat('en-US', {
     timeZone: tz, hour12: false,
     year: 'numeric', month: '2-digit', day: '2-digit',
diff --git a/client/src/components/Notifications/InAppNotificationItem.tsx b/client/src/components/Notifications/InAppNotificationItem.tsx
index 369af6cdc..e95a0f1f2 100644
--- a/client/src/components/Notifications/InAppNotificationItem.tsx
+++ b/client/src/components/Notifications/InAppNotificationItem.tsx
@@ -92,7 +92,7 @@ export default function InAppNotificationItem({ notification, onClose }: Notific
                 {relativeTime(notification.created_at, locale)}
               </span>
               {!notification.is_read && (
-                <button
+                <button type="button"
                   onClick={() => markRead(notification.id)}
                   title={t('notifications.markRead')}
                   className="p-1 rounded transition-colors"
@@ -103,7 +103,7 @@ export default function InAppNotificationItem({ notification, onClose }: Notific
                   <CheckCheck className="w-3.5 h-3.5" />
                 </button>
               )}
-              <button
+              <button type="button"
                 onClick={() => deleteNotification(notification.id)}
                 title={t('notifications.delete')}
                 className="p-1 rounded transition-colors"
@@ -123,7 +123,7 @@ export default function InAppNotificationItem({ notification, onClose }: Notific
           {/* Boolean actions */}
           {notification.type === 'boolean' && notification.positive_text_key && notification.negative_text_key && (
             <div className="flex gap-2 mt-2">
-              <button
+              <button type="button"
                 onClick={() => handleRespond('positive')}
                 disabled={responding || notification.response !== null}
                 className="flex items-center gap-1 px-2.5 py-1 rounded-lg text-xs font-medium transition-colors"
@@ -145,7 +145,7 @@ export default function InAppNotificationItem({ notification, onClose }: Notific
                 <Check className="w-3 h-3" />
                 {t(notification.positive_text_key)}
               </button>
-              <button
+              <button type="button"
                 onClick={() => handleRespond('negative')}
                 disabled={responding || notification.response !== null}
                 className="flex items-center gap-1 px-2.5 py-1 rounded-lg text-xs font-medium transition-colors"
@@ -172,7 +172,7 @@ export default function InAppNotificationItem({ notification, onClose }: Notific
 
           {/* Navigate action */}
           {notification.type === 'navigate' && notification.navigate_text_key && notification.navigate_target && (
-            <button
+            <button type="button"
               onClick={handleNavigate}
               className="flex items-center gap-1 mt-2 px-2.5 py-1 rounded-lg text-xs font-medium transition-colors"
               style={{ background: dark ? '#27272a' : '#f1f5f9', color: 'var(--text-secondary)' }}
diff --git a/client/src/components/PDF/TripPDF.tsx b/client/src/components/PDF/TripPDF.tsx
index 7e531f4d8..7574a8732 100644
--- a/client/src/components/PDF/TripPDF.tsx
+++ b/client/src/components/PDF/TripPDF.tsx
@@ -132,7 +132,7 @@ function longDateRange(days, locale) {
 // unavailable (#1561).
 function dayCost(assignments, dayId, locale, tripCurrency, rates) {
   const entries: MoneyEntry[] = (assignments[String(dayId)] || []).map(a => ({
-    amount: parseFloat(a.place?.price) || 0,
+    amount: Number.parseFloat(a.place?.price) || 0,
     currency: a.place?.currency || tripCurrency,
   }))
   return formatMoneySum(entries, tripCurrency, locale || 'en', rates)
@@ -413,7 +413,7 @@ export async function downloadTripPDF({ trip, days, places, assignments = {}, ca
 
           const chips = [
             place.place_time ? `<span class="chip">${svgClock}${escHtml(place.place_time)}</span>` : '',
-            place.price && parseFloat(place.price) > 0 ? `<span class="chip chip-green">${svgMoney}${formatMoney(Number(place.price), place.currency || trip.currency, loc)}</span>` : '',
+            place.price && Number.parseFloat(place.price) > 0 ? `<span class="chip chip-green">${svgMoney}${formatMoney(Number(place.price), place.currency || trip.currency, loc)}</span>` : '',
           ].filter(Boolean).join('')
 
           return `
@@ -766,8 +766,8 @@ ${pluginSectionsHtml}
       <button id="pdf-daybreak-toggle" type="button" role="switch" aria-checked="${breaksPerDay}" aria-label="${escHtml(tr('pdf.pageBreakPerDay'))}" style="${TOGGLE_TRACK} background:${trackColour(breaksPerDay)}">
         <span style="${TOGGLE_KNOB} left:${knobOffset(breaksPerDay)}"></span>
       </button>
-      <button id="pdf-print-btn" style="display:flex;align-items:center;gap:5px;font-size:12px;font-weight:500;color:var(--text-muted);background:none;border:none;cursor:pointer;padding:4px 8px;border-radius:6px;font-family:inherit">${tr('pdf.saveAsPdf')}</button>
-      <button id="pdf-close-btn" style="background:none;border:none;cursor:pointer;color:var(--text-faint);display:flex;padding:4px;border-radius:6px">
+      <button type="button" id="pdf-print-btn" style="display:flex;align-items:center;gap:5px;font-size:12px;font-weight:500;color:var(--text-muted);background:none;border:none;cursor:pointer;padding:4px 8px;border-radius:6px;font-family:inherit">${tr('pdf.saveAsPdf')}</button>
+      <button type="button" id="pdf-close-btn" style="background:none;border:none;cursor:pointer;color:var(--text-faint);display:flex;padding:4px;border-radius:6px">
         <svg width="18" height="18" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round"><line x1="18" y1="6" x2="6" y2="18"/><line x1="6" y1="6" x2="18" y2="18"/></svg>
       </button>
     </div>
diff --git a/client/src/components/Packing/ApplyTemplateButton.tsx b/client/src/components/Packing/ApplyTemplateButton.tsx
index 7fa920f98..01de45335 100644
--- a/client/src/components/Packing/ApplyTemplateButton.tsx
+++ b/client/src/components/Packing/ApplyTemplateButton.tsx
@@ -59,7 +59,7 @@ export default function ApplyTemplateButton({ tripId, visibility, style, classNa
 
   return (
     <div ref={dropRef} style={{ position: 'relative' }}>
-      <button
+      <button type="button"
         onClick={() => setOpen(v => !v)}
         disabled={applying}
         className={className ?? 'hover:opacity-[0.88]'}
@@ -79,7 +79,7 @@ export default function ApplyTemplateButton({ tripId, visibility, style, classNa
           }}
         >
           {templates.map(tmpl => (
-            <button key={tmpl.id} onClick={() => handleApply(tmpl.id)}
+            <button type="button" key={tmpl.id} onClick={() => handleApply(tmpl.id)}
               style={{
                 display: 'flex', alignItems: 'center', gap: 8, width: '100%',
                 padding: '8px 12px', borderRadius: 8, border: 'none', cursor: 'pointer',
diff --git a/client/src/components/Packing/PackingListPanelBagCard.tsx b/client/src/components/Packing/PackingListPanelBagCard.tsx
index bd3f63a82..1b275d1f4 100644
--- a/client/src/components/Packing/PackingListPanelBagCard.tsx
+++ b/client/src/components/Packing/PackingListPanelBagCard.tsx
@@ -79,13 +79,13 @@ export function BagCard({ bag, bagItems, totalWeight, pct, tripId, tripMembers,
               / {(bag.weight_limit_grams / 1000).toFixed(1)} kg
             </span>
           ) : canEdit ? (
-            <button onClick={() => setEditingLimit(true)} title={t('packing.bagLimit')}
+            <button type="button" onClick={() => setEditingLimit(true)} title={t('packing.bagLimit')}
               style={{ background: 'none', border: 'none', padding: 0, cursor: 'pointer', color: 'var(--text-faint)', fontSize: sz.count, fontFamily: 'inherit', textDecoration: 'underline dotted' }}>
               {t('packing.setBagLimit')}
             </button>
           ) : null}
         </span>
-        {canEdit && <button onClick={onDelete} style={{ background: 'none', border: 'none', cursor: 'pointer', padding: 2, color: 'var(--text-faint)', display: 'flex' }}><X size={sz.icon} /></button>}
+        {canEdit && <button type="button" onClick={onDelete} style={{ background: 'none', border: 'none', cursor: 'pointer', padding: 2, color: 'var(--text-faint)', display: 'flex' }}><X size={sz.icon} /></button>}
       </div>
       {/* Members */}
       <div style={{ display: 'flex', alignItems: 'center', gap: 4, marginBottom: 4, flexWrap: 'wrap', position: 'relative' }}>
@@ -101,7 +101,7 @@ export function BagCard({ bag, bagItems, totalWeight, pct, tripId, tripMembers,
           </span>
         ))}
         {canEdit && (
-          <button onClick={() => setShowUserPicker(v => !v)} style={{ width: sz.avatar, height: sz.avatar, borderRadius: '50%', border: '1.5px dashed var(--border-primary)', background: 'none', color: 'var(--text-faint)', cursor: 'pointer', display: 'flex', alignItems: 'center', justifyContent: 'center', padding: 0, boxSizing: 'border-box' }}>
+          <button type="button" onClick={() => setShowUserPicker(v => !v)} style={{ width: sz.avatar, height: sz.avatar, borderRadius: '50%', border: '1.5px dashed var(--border-primary)', background: 'none', color: 'var(--text-faint)', cursor: 'pointer', display: 'flex', alignItems: 'center', justifyContent: 'center', padding: 0, boxSizing: 'border-box' }}>
             <Plus size={sz.avatar * 0.5} />
           </button>
         )}
@@ -110,7 +110,7 @@ export function BagCard({ bag, bagItems, totalWeight, pct, tripId, tripMembers,
             {tripMembers.map(m => {
               const isSelected = memberIds.includes(m.id)
               return (
-                <button key={m.id} onClick={() => { toggleMember(m.id); }}
+                <button type="button" key={m.id} onClick={() => { toggleMember(m.id); }}
                   style={{ display: 'flex', alignItems: 'center', gap: 8, width: '100%', padding: '6px 10px', borderRadius: 6, border: 'none', background: isSelected ? 'var(--bg-tertiary)' : 'transparent', cursor: 'pointer', fontSize: 'calc(11px * var(--fs-scale-caption, 1))', color: 'var(--text-primary)', fontFamily: 'inherit' }}
                   onMouseEnter={e => { if (!isSelected) e.currentTarget.style.background = 'var(--bg-secondary)' }}
                   onMouseLeave={e => { if (!isSelected) e.currentTarget.style.background = 'transparent' }}>
@@ -128,7 +128,7 @@ export function BagCard({ bag, bagItems, totalWeight, pct, tripId, tripMembers,
             })}
             {tripMembers.length === 0 && <div style={{ padding: '8px 10px', fontSize: 'calc(11px * var(--fs-scale-caption, 1))', color: 'var(--text-faint)' }}>{t('packing.noMembers')}</div>}
             <div style={{ borderTop: '1px solid var(--border-secondary)', marginTop: 4, paddingTop: 4 }}>
-              <button onClick={() => setShowUserPicker(false)} style={{ width: '100%', padding: '6px 10px', borderRadius: 6, border: 'none', background: 'transparent', cursor: 'pointer', fontSize: 'calc(11px * var(--fs-scale-caption, 1))', color: 'var(--text-faint)', fontFamily: 'inherit', textAlign: 'center' }}>
+              <button type="button" onClick={() => setShowUserPicker(false)} style={{ width: '100%', padding: '6px 10px', borderRadius: 6, border: 'none', background: 'transparent', cursor: 'pointer', fontSize: 'calc(11px * var(--fs-scale-caption, 1))', color: 'var(--text-faint)', fontFamily: 'inherit', textAlign: 'center' }}>
                 {t('common.close')}
               </button>
             </div>
diff --git a/client/src/components/Packing/PackingListPanelBagModal.tsx b/client/src/components/Packing/PackingListPanelBagModal.tsx
index 650ce8632..268b5496c 100644
--- a/client/src/components/Packing/PackingListPanelBagModal.tsx
+++ b/client/src/components/Packing/PackingListPanelBagModal.tsx
@@ -20,7 +20,7 @@ export function BagModal(S: PackingState) {
         onClick={e => e.stopPropagation()}>
         <div style={{ display: 'flex', alignItems: 'center', justifyContent: 'space-between', marginBottom: 16 }}>
           <h3 style={{ margin: 0, fontSize: 'calc(16px * var(--fs-scale-subtitle, 1))', fontWeight: 700, color: 'var(--text-primary)' }}>{t('packing.bags')}</h3>
-          <button onClick={() => setShowBagModal(false)} style={{ background: 'none', border: 'none', cursor: 'pointer', color: 'var(--text-faint)', display: 'flex' }}><X size={18} /></button>
+          <button type="button" onClick={() => setShowBagModal(false)} style={{ background: 'none', border: 'none', cursor: 'pointer', color: 'var(--text-faint)', display: 'flex' }}><X size={18} /></button>
         </div>
 
         {bags.map(bag => {
@@ -66,13 +66,13 @@ export function BagModal(S: PackingState) {
               onKeyDown={e => { if (e.key === 'Enter') handleCreateBag(); if (e.key === 'Escape') { setShowAddBag(false); setNewBagName('') } }}
               placeholder={t('packing.bagName')}
               style={{ flex: 1, padding: '8px 12px', borderRadius: 10, border: '1px solid var(--border-primary)', fontSize: 'calc(13px * var(--fs-scale-body, 1))', fontFamily: 'inherit', outline: 'none' }} />
-            <button onClick={handleCreateBag} disabled={!newBagName.trim()}
+            <button type="button" onClick={handleCreateBag} disabled={!newBagName.trim()}
               style={{ padding: '8px 12px', borderRadius: 10, border: 'none', background: newBagName.trim() ? 'var(--text-primary)' : 'var(--border-primary)', color: 'var(--bg-primary)', cursor: newBagName.trim() ? 'pointer' : 'default', display: 'flex', alignItems: 'center' }}>
               <Plus size={14} />
             </button>
           </div>
         ) : (
-          <button onClick={() => setShowAddBag(true)}
+          <button type="button" onClick={() => setShowAddBag(true)}
             style={{ display: 'flex', alignItems: 'center', gap: 6, marginTop: 14, padding: '9px 14px', borderRadius: 10, border: '1px dashed var(--border-primary)', background: 'none', cursor: 'pointer', fontSize: 'calc(13px * var(--fs-scale-body, 1))', color: 'var(--text-faint)', fontFamily: 'inherit', width: '100%', transition: 'all 0.15s' }}
             onMouseEnter={e => { e.currentTarget.style.borderColor = 'var(--text-muted)'; e.currentTarget.style.color = 'var(--text-secondary)' }}
             onMouseLeave={e => { e.currentTarget.style.borderColor = 'var(--border-primary)'; e.currentTarget.style.color = 'var(--text-faint)' }}>
diff --git a/client/src/components/Packing/PackingListPanelBagSidebar.tsx b/client/src/components/Packing/PackingListPanelBagSidebar.tsx
index f3c994021..eac5b044d 100644
--- a/client/src/components/Packing/PackingListPanelBagSidebar.tsx
+++ b/client/src/components/Packing/PackingListPanelBagSidebar.tsx
@@ -62,12 +62,12 @@ export function BagSidebar(S: PackingState) {
             onKeyDown={e => { if (e.key === 'Enter') handleCreateBag(); if (e.key === 'Escape') { setShowAddBag(false); setNewBagName('') } }}
             placeholder={t('packing.bagName')}
             style={{ flex: 1, padding: '5px 8px', borderRadius: 8, border: '1px solid var(--border-primary)', fontSize: 'calc(11px * var(--fs-scale-caption, 1))', fontFamily: 'inherit', outline: 'none' }} />
-          <button onClick={handleCreateBag} style={{ padding: '4px 8px', borderRadius: 8, border: 'none', background: 'var(--text-primary)', color: 'var(--bg-primary)', cursor: 'pointer', display: 'flex', alignItems: 'center' }}>
+          <button type="button" onClick={handleCreateBag} style={{ padding: '4px 8px', borderRadius: 8, border: 'none', background: 'var(--text-primary)', color: 'var(--bg-primary)', cursor: 'pointer', display: 'flex', alignItems: 'center' }}>
             <Plus size={12} />
           </button>
         </div>
       ) : (
-        <button onClick={() => setShowAddBag(true)}
+        <button type="button" onClick={() => setShowAddBag(true)}
           style={{ display: 'flex', alignItems: 'center', gap: 4, marginTop: 12, padding: '5px 8px', borderRadius: 8, border: '1px dashed var(--border-primary)', background: 'none', cursor: 'pointer', fontSize: 'calc(11px * var(--fs-scale-caption, 1))', color: 'var(--text-faint)', fontFamily: 'inherit', width: '100%' }}>
           <Plus size={11} /> {t('packing.addBag')}
         </button>
diff --git a/client/src/components/Packing/PackingListPanelCategoryGroup.tsx b/client/src/components/Packing/PackingListPanelCategoryGroup.tsx
index 8c2bad168..b31beb2d0 100644
--- a/client/src/components/Packing/PackingListPanelCategoryGroup.tsx
+++ b/client/src/components/Packing/PackingListPanelCategoryGroup.tsx
@@ -115,7 +115,7 @@ export function KategorieGruppe({ kategorie, items, tripId, allCategories, onRen
   return (
     <div style={{ marginBottom: 6, background: 'var(--bg-card)', borderRadius: 14, border: '1px solid var(--border-secondary)', overflow: 'visible' }}>
       <div style={{ display: 'flex', alignItems: 'center', gap: 8, padding: '10px 12px', borderBottom: offen ? '1px solid var(--border-secondary)' : 'none' }}>
-        <button onClick={() => setOffen(o => !o)} style={{ background: 'none', border: 'none', cursor: 'pointer', padding: 0, display: 'flex', color: 'var(--text-faint)', flexShrink: 0 }}>
+        <button type="button" onClick={() => setOffen(o => !o)} style={{ background: 'none', border: 'none', cursor: 'pointer', padding: 0, display: 'flex', color: 'var(--text-faint)', flexShrink: 0 }}>
           {offen ? <ChevronDown size={15} /> : <ChevronRight size={15} />}
         </button>
 
@@ -165,7 +165,7 @@ export function KategorieGruppe({ kategorie, items, tripId, allCategories, onRen
           ))}
           {canEdit && (
           <div ref={assigneeDropdownRef} style={{ position: 'relative' }}>
-            <button onClick={e => { e.stopPropagation(); setShowAssigneeDropdown(v => !v) }}
+            <button type="button" onClick={e => { e.stopPropagation(); setShowAssigneeDropdown(v => !v) }}
               style={{
                 width: 20, height: 20, borderRadius: '50%', border: '1.5px dashed var(--border-primary)',
                 background: 'none', cursor: 'pointer', display: 'flex', alignItems: 'center', justifyContent: 'center',
@@ -185,7 +185,7 @@ export function KategorieGruppe({ kategorie, items, tripId, allCategories, onRen
                 {tripMembers.map(m => {
                   const isAssigned = assignees.some(a => a.user_id === m.id)
                   return (
-                    <button key={m.id} onClick={e => {
+                    <button type="button" key={m.id} onClick={e => {
                       e.stopPropagation()
                       const newIds = isAssigned
                         ? assignees.filter(a => a.user_id !== m.id).map(a => a.user_id)
@@ -236,7 +236,7 @@ export function KategorieGruppe({ kategorie, items, tripId, allCategories, onRen
         </span>
 
         <div style={{ position: 'relative' }}>
-          <button ref={menuBtnRef} onClick={() => setShowMenu(m => !m)} style={{ background: 'none', border: 'none', cursor: 'pointer', padding: '2px 4px', borderRadius: 6, display: 'flex', color: 'var(--text-faint)' }}
+          <button type="button" ref={menuBtnRef} onClick={() => setShowMenu(m => !m)} style={{ background: 'none', border: 'none', cursor: 'pointer', padding: '2px 4px', borderRadius: 6, display: 'flex', color: 'var(--text-faint)' }}
             onMouseEnter={e => e.currentTarget.style.color = 'var(--text-secondary)'} onMouseLeave={e => e.currentTarget.style.color = 'var(--text-faint)'}>
             <MoreHorizontal size={15} />
           </button>
@@ -300,18 +300,18 @@ export function KategorieGruppe({ kategorie, items, tripId, allCategories, onRen
                 style={{ flex: 1, padding: '6px 10px', borderRadius: 8, border: '1px solid var(--border-primary)', fontSize: 'calc(12.5px * var(--fs-scale-body, 1))', fontFamily: 'inherit', outline: 'none', color: 'var(--text-primary)', background: 'var(--bg-input)' }}
               />
               {/* disabled while the field is empty, so no extra guard here */}
-              <button onClick={() => { onAddItem(kategorie, newItemName.trim()); setNewItemName(''); setTimeout(() => addItemRef.current?.focus(), 30) }}
+              <button type="button" onClick={() => { onAddItem(kategorie, newItemName.trim()); setNewItemName(''); setTimeout(() => addItemRef.current?.focus(), 30) }}
                 disabled={!newItemName.trim()}
                 style={{ padding: '5px 8px', borderRadius: 8, border: 'none', background: newItemName.trim() ? 'var(--text-primary)' : 'var(--border-primary)', color: 'var(--bg-primary)', cursor: newItemName.trim() ? 'pointer' : 'default', display: 'flex' }}>
                 <Plus size={14} />
               </button>
-              <button onClick={() => { setShowAddItem(false); setNewItemName('') }}
+              <button type="button" onClick={() => { setShowAddItem(false); setNewItemName('') }}
                 style={{ background: 'none', border: 'none', cursor: 'pointer', padding: 2, display: 'flex', color: 'var(--text-faint)' }}>
                 <X size={14} />
               </button>
             </div>
           ) : (
-            <button onClick={() => { setShowAddItem(true); setTimeout(() => addItemRef.current?.focus(), 30) }}
+            <button type="button" onClick={() => { setShowAddItem(true); setTimeout(() => addItemRef.current?.focus(), 30) }}
               style={{ display: 'flex', alignItems: 'center', gap: 5, padding: '5px 10px', margin: '2px 4px', borderRadius: 8, border: 'none', background: 'none', cursor: 'pointer', fontSize: 'calc(12px * var(--fs-scale-body, 1))', color: 'var(--text-faint)', fontFamily: 'inherit' }}
               onMouseEnter={e => e.currentTarget.style.color = 'var(--text-secondary)'}
               onMouseLeave={e => e.currentTarget.style.color = 'var(--text-faint)'}>
@@ -333,7 +333,7 @@ interface MenuItemProps {
 
 function MenuItem({ icon, label, onClick, danger = false }: MenuItemProps) {
   return (
-    <button onClick={onClick} style={{
+    <button type="button" onClick={onClick} style={{
       display: 'flex', alignItems: 'center', gap: 8, width: '100%',
       padding: '7px 10px', background: 'none', border: 'none', cursor: 'pointer',
       fontSize: 'calc(12.5px * var(--fs-scale-body, 1))', fontFamily: 'inherit', borderRadius: 7, textAlign: 'left',
diff --git a/client/src/components/Packing/PackingListPanelHeader.tsx b/client/src/components/Packing/PackingListPanelHeader.tsx
index 4e49baa36..3e6cc2085 100644
--- a/client/src/components/Packing/PackingListPanelHeader.tsx
+++ b/client/src/components/Packing/PackingListPanelHeader.tsx
@@ -36,12 +36,12 @@ export function PackingHeader(S: PackingState) {
                 placeholder={t('packing.templateName')}
                 style={{ fontSize: 'calc(12px * var(--fs-scale-body, 1))', padding: '5px 10px', borderRadius: 99, border: '1px solid var(--border-primary)', outline: 'none', fontFamily: 'inherit', width: 140, background: 'var(--bg-card)', color: 'var(--text-primary)' }}
               />
-              <button onClick={handleSaveAsTemplate} style={{ background: 'none', border: 'none', cursor: 'pointer', padding: 2, color: '#10b981' }}><Check size={14} /></button>
-              <button onClick={() => { setShowSaveTemplate(false); setSaveTemplateName('') }} style={{ background: 'none', border: 'none', cursor: 'pointer', padding: 2, color: 'var(--text-faint)' }}><X size={14} /></button>
+              <button type="button" onClick={handleSaveAsTemplate} style={{ background: 'none', border: 'none', cursor: 'pointer', padding: 2, color: '#10b981' }}><Check size={14} /></button>
+              <button type="button" onClick={() => { setShowSaveTemplate(false); setSaveTemplateName('') }} style={{ background: 'none', border: 'none', cursor: 'pointer', padding: 2, color: 'var(--text-faint)' }}><X size={14} /></button>
             </div>
           )}
           {inlineHeader && canEdit && (
-            <button onClick={() => setShowImportModal(true)} style={{
+            <button type="button" onClick={() => setShowImportModal(true)} style={{
               display: 'flex', alignItems: 'center', gap: 5, padding: '5px 11px', borderRadius: 99,
               border: '1px solid var(--border-primary)', fontSize: 'calc(12px * var(--fs-scale-body, 1))', fontWeight: 500, cursor: 'pointer',
               fontFamily: 'inherit', background: 'var(--bg-card)', color: 'var(--text-muted)',
@@ -50,7 +50,7 @@ export function PackingHeader(S: PackingState) {
             </button>
           )}
           {inlineHeader && canEdit && abgehakt > 0 && (
-            <button onClick={handleClearChecked} style={{
+            <button type="button" onClick={handleClearChecked} style={{
               fontSize: 'calc(11.5px * var(--fs-scale-caption, 1))', padding: '5px 10px', borderRadius: 99, border: '1px solid rgba(239,68,68,0.3)',
               background: 'rgba(239,68,68,0.1)', color: '#ef4444', cursor: 'pointer', fontFamily: 'inherit',
             }}>
@@ -60,7 +60,7 @@ export function PackingHeader(S: PackingState) {
           )}
           {inlineHeader && canEdit && availableTemplates.length > 0 && (
             <div ref={templateDropdownRef} style={{ position: 'relative' }}>
-              <button onClick={() => setShowTemplateDropdown(v => !v)} disabled={applyingTemplate} style={{
+              <button type="button" onClick={() => setShowTemplateDropdown(v => !v)} disabled={applyingTemplate} style={{
                 display: 'flex', alignItems: 'center', gap: 5, padding: '5px 11px', borderRadius: 99,
                 border: '1px solid', fontSize: 'calc(12px * var(--fs-scale-body, 1))', fontWeight: 500, cursor: 'pointer', fontFamily: 'inherit',
                 background: showTemplateDropdown ? 'var(--text-primary)' : 'var(--bg-card)',
@@ -76,7 +76,7 @@ export function PackingHeader(S: PackingState) {
                   boxShadow: '0 4px 16px rgba(0,0,0,0.12)', padding: 4, minWidth: 200,
                 }}>
                   {availableTemplates.map(tmpl => (
-                    <button key={tmpl.id} onClick={() => handleApplyTemplate(tmpl.id)}
+                    <button type="button" key={tmpl.id} onClick={() => handleApplyTemplate(tmpl.id)}
                       style={{
                         display: 'flex', alignItems: 'center', gap: 8, width: '100%',
                         padding: '8px 12px', borderRadius: 8, border: 'none', cursor: 'pointer',
@@ -98,7 +98,7 @@ export function PackingHeader(S: PackingState) {
             </div>
           )}
           {inlineHeader && canEdit && isAdmin && items.length > 0 && !showSaveTemplate && (
-            <button onClick={() => setShowSaveTemplate(true)} style={{
+            <button type="button" onClick={() => setShowSaveTemplate(true)} style={{
               display: 'flex', alignItems: 'center', gap: 5, padding: '5px 11px', borderRadius: 99,
               border: '1px solid var(--border-primary)', fontSize: 'calc(12px * var(--fs-scale-body, 1))', fontWeight: 500, cursor: 'pointer', fontFamily: 'inherit',
               background: 'var(--bg-card)', color: 'var(--text-muted)',
@@ -107,7 +107,7 @@ export function PackingHeader(S: PackingState) {
             </button>
           )}
           {bagTrackingEnabled && (
-            <button onClick={() => setShowBagModal(true)} className="xl:!hidden"
+            <button type="button" onClick={() => setShowBagModal(true)} className="xl:!hidden"
               style={{
                 display: 'flex', alignItems: 'center', gap: 5, padding: '5px 11px', borderRadius: 99,
                 border: '1px solid', fontSize: 'calc(12px * var(--fs-scale-body, 1))', fontWeight: 500, cursor: 'pointer', fontFamily: 'inherit',
@@ -197,17 +197,17 @@ export function PackingHeader(S: PackingState) {
             placeholder={t('packing.newCategoryPlaceholder')}
             style={{ flex: 1, padding: '8px 12px', borderRadius: 10, border: '1px solid var(--border-primary)', fontSize: 'calc(13.5px * var(--fs-scale-body, 1))', fontFamily: 'inherit', outline: 'none', color: 'var(--text-primary)' }}
           />
-          <button onClick={handleAddNewCategory} disabled={!newCatName.trim()}
+          <button type="button" onClick={handleAddNewCategory} disabled={!newCatName.trim()}
             style={{ padding: '8px 12px', borderRadius: 10, border: 'none', background: newCatName.trim() ? 'var(--text-primary)' : 'var(--border-primary)', color: 'var(--bg-primary)', cursor: newCatName.trim() ? 'pointer' : 'default', display: 'flex', alignItems: 'center' }}>
             <Check size={16} />
           </button>
-          <button onClick={() => { setAddingCategory(false); setNewCatName('') }}
+          <button type="button" onClick={() => { setAddingCategory(false); setNewCatName('') }}
             style={{ padding: '8px 12px', borderRadius: 10, border: '1px solid var(--border-primary)', background: 'none', cursor: 'pointer', display: 'flex', alignItems: 'center', color: 'var(--text-faint)' }}>
             <X size={16} />
           </button>
         </div>
       ) : (
-        <button onClick={() => setAddingCategory(true)}
+        <button type="button" onClick={() => setAddingCategory(true)}
           style={{ display: 'flex', alignItems: 'center', gap: 6, width: '100%', padding: '9px 14px', borderRadius: 10, border: '1px dashed var(--border-primary)', background: 'none', cursor: 'pointer', fontSize: 'calc(13px * var(--fs-scale-body, 1))', color: 'var(--text-faint)', fontFamily: 'inherit', transition: 'all 0.15s' }}
           onMouseEnter={e => { e.currentTarget.style.borderColor = 'var(--text-muted)'; e.currentTarget.style.color = 'var(--text-secondary)' }}
           onMouseLeave={e => { e.currentTarget.style.borderColor = 'var(--border-primary)'; e.currentTarget.style.color = 'var(--text-faint)' }}>
diff --git a/client/src/components/Packing/PackingListPanelImportModal.tsx b/client/src/components/Packing/PackingListPanelImportModal.tsx
index 05285acf5..1f1faed84 100644
--- a/client/src/components/Packing/PackingListPanelImportModal.tsx
+++ b/client/src/components/Packing/PackingListPanelImportModal.tsx
@@ -43,7 +43,7 @@ export function BulkImportModal(S: PackingState) {
         <div style={{ display: 'flex', alignItems: 'center', justifyContent: 'space-between' }}>
           <div>
             <input ref={csvInputRef} type="file" accept=".csv,.txt" style={{ display: 'none' }} onChange={handleCsvFile} />
-            <button onClick={() => csvInputRef.current?.click()} style={{
+            <button type="button" onClick={() => csvInputRef.current?.click()} style={{
               display: 'flex', alignItems: 'center', gap: 5, padding: '5px 10px',
               border: '1px dashed var(--border-primary)', borderRadius: 8, background: 'none',
               fontSize: 'calc(11px * var(--fs-scale-caption, 1))', color: 'var(--text-faint)', cursor: 'pointer', fontFamily: 'inherit',
@@ -52,11 +52,11 @@ export function BulkImportModal(S: PackingState) {
             </button>
           </div>
           <div style={{ display: 'flex', gap: 8 }}>
-            <button onClick={() => setShowImportModal(false)} style={{
+            <button type="button" onClick={() => setShowImportModal(false)} style={{
               fontSize: 'calc(12px * var(--fs-scale-body, 1))', background: 'none', border: '1px solid var(--border-primary)',
               borderRadius: 8, padding: '6px 14px', cursor: 'pointer', color: 'var(--text-muted)', fontFamily: 'inherit',
             }}>{t('common.cancel')}</button>
-            <button onClick={handleBulkImport} disabled={!importText.trim()} style={{
+            <button type="button" onClick={handleBulkImport} disabled={!importText.trim()} style={{
               fontSize: 'calc(12px * var(--fs-scale-body, 1))', background: 'var(--accent)', color: 'var(--accent-text)',
               border: 'none', borderRadius: 8, padding: '6px 16px', cursor: 'pointer', fontWeight: 600,
               fontFamily: 'inherit', opacity: importText.trim() ? 1 : 0.5,
diff --git a/client/src/components/Packing/PackingListPanelItemRow.tsx b/client/src/components/Packing/PackingListPanelItemRow.tsx
index debeb1d42..4ca8b65f3 100644
--- a/client/src/components/Packing/PackingListPanelItemRow.tsx
+++ b/client/src/components/Packing/PackingListPanelItemRow.tsx
@@ -122,7 +122,7 @@ export function ArtikelZeile({ item, tripId, categories, onCategoryChange: _onCa
           <GripVertical size={13} />
         </div>
       )}
-      <button onClick={handleToggle} style={{
+      <button type="button" onClick={handleToggle} style={{
         flexShrink: 0, background: 'none', border: 'none', cursor: 'pointer', padding: 0, position: 'relative',
         width: 18, height: 18,
         color: item.checked ? '#10b981' : 'var(--text-faint)',
@@ -200,7 +200,7 @@ export function ArtikelZeile({ item, tripId, categories, onCategoryChange: _onCa
               readOnly={!canEdit}
               onValueChange={async raw => {
                 if (!canEdit) return
-                const v = raw === '' ? null : parseInt(raw)
+                const v = raw === '' ? null : Number.parseInt(raw)
                 try { await updatePackingItem(tripId, item.id, { weight_grams: v }) } catch { toast.error(t('packing.toast.saveError')) }
               }}
               placeholder="—"
@@ -209,7 +209,7 @@ export function ArtikelZeile({ item, tripId, categories, onCategoryChange: _onCa
             <span style={{ fontSize: 'calc(10px * var(--fs-scale-caption, 1))', color: 'var(--text-faint)', userSelect: 'none' }}>g</span>
           </div>
           <div style={{ position: 'relative' }}>
-            <button
+            <button type="button"
               onClick={() => canEdit && setShowBagPicker(p => !p)}
               style={{
                 width: 22, height: 22, borderRadius: '50%', cursor: canEdit ? 'pointer' : 'default', padding: 0, display: 'flex', alignItems: 'center', justifyContent: 'center',
@@ -226,14 +226,14 @@ export function ArtikelZeile({ item, tripId, categories, onCategoryChange: _onCa
                 boxShadow: '0 4px 16px rgba(0,0,0,0.12)', padding: 4, minWidth: 160,
               }}>
                 {item.bag_id && (
-                  <button onClick={async () => { setShowBagPicker(false); try { await updatePackingItem(tripId, item.id, { bag_id: null }) } catch { toast.error(t('packing.toast.saveError')) } }}
+                  <button type="button" onClick={async () => { setShowBagPicker(false); try { await updatePackingItem(tripId, item.id, { bag_id: null }) } catch { toast.error(t('packing.toast.saveError')) } }}
                     style={{ display: 'flex', alignItems: 'center', gap: 7, width: '100%', padding: '6px 10px', background: 'none', border: 'none', cursor: 'pointer', fontSize: 'calc(12px * var(--fs-scale-body, 1))', fontFamily: 'inherit', color: 'var(--text-faint)', borderRadius: 7 }}>
                     <span style={{ width: 10, height: 10, borderRadius: '50%', border: '2px dashed var(--border-primary)' }} />
                     {t('packing.noBag')}
                   </button>
                 )}
                 {bags.map(b => (
-                  <button key={b.id} onClick={async () => { setShowBagPicker(false); try { await updatePackingItem(tripId, item.id, { bag_id: b.id }) } catch { toast.error(t('packing.toast.saveError')) } }}
+                  <button type="button" key={b.id} onClick={async () => { setShowBagPicker(false); try { await updatePackingItem(tripId, item.id, { bag_id: b.id }) } catch { toast.error(t('packing.toast.saveError')) } }}
                     style={{
                       display: 'flex', alignItems: 'center', gap: 7, width: '100%', padding: '6px 10px',
                       background: item.bag_id === b.id ? 'var(--bg-tertiary)' : 'none',
@@ -260,7 +260,7 @@ export function ArtikelZeile({ item, tripId, categories, onCategoryChange: _onCa
                         }}
                         placeholder={t('packing.bagName')}
                         style={{ flex: 1, padding: '4px 8px', borderRadius: 6, border: '1px solid var(--border-primary)', fontSize: 'calc(11px * var(--fs-scale-caption, 1))', fontFamily: 'inherit', outline: 'none' }} />
-                      <button onClick={async () => {
+                      <button type="button" onClick={async () => {
                         if (bagInlineName.trim()) {
                           const newBag = await onCreateBag(bagInlineName.trim())
                           if (newBag) { try { await updatePackingItem(tripId, item.id, { bag_id: newBag.id }) } catch { toast.error(t('packing.toast.saveError')) } }
@@ -272,7 +272,7 @@ export function ArtikelZeile({ item, tripId, categories, onCategoryChange: _onCa
                       </button>
                     </div>
                   ) : (
-                    <button onClick={() => setBagInlineCreate(true)}
+                    <button type="button" onClick={() => setBagInlineCreate(true)}
                       style={{ display: 'flex', alignItems: 'center', gap: 5, width: '100%', padding: '5px 6px', background: 'none', border: 'none', cursor: 'pointer', fontSize: 'calc(11px * var(--fs-scale-caption, 1))', fontFamily: 'inherit', color: 'var(--text-faint)', borderRadius: 7 }}
                       onMouseEnter={e => e.currentTarget.style.color = 'var(--text-secondary)'}
                       onMouseLeave={e => e.currentTarget.style.color = 'var(--text-faint)'}>
@@ -290,7 +290,7 @@ export function ArtikelZeile({ item, tripId, categories, onCategoryChange: _onCa
       {canEdit && (
       <div className="packing-row-inline-actions" style={{ display: 'flex', gap: 2, alignItems: 'center', flexShrink: 0 }}>
         <div style={{ position: 'relative' }}>
-          <button
+          <button type="button"
             onClick={() => setShowCatPicker(p => !p)}
             title={t('packing.changeCategory')}
             style={{ background: 'none', border: 'none', cursor: 'pointer', padding: '3px 5px', borderRadius: 6, display: 'flex', alignItems: 'center', color: 'var(--text-faint)', fontSize: 'calc(10px * var(--fs-scale-caption, 1))', gap: 2 }}
@@ -304,7 +304,7 @@ export function ArtikelZeile({ item, tripId, categories, onCategoryChange: _onCa
               padding: 4, minWidth: 140,
             }}>
               {categories.map(cat => (
-                <button key={cat} onClick={() => handleCatChange(cat)} style={{
+                <button type="button" key={cat} onClick={() => handleCatChange(cat)} style={{
                   display: 'flex', alignItems: 'center', gap: 7, width: '100%',
                   padding: '6px 10px', background: cat === (item.category || t('packing.defaultCategory')) ? 'var(--bg-tertiary)' : 'none',
                   border: 'none', cursor: 'pointer', fontSize: 'calc(12.5px * var(--fs-scale-body, 1))', fontFamily: 'inherit',
@@ -330,12 +330,12 @@ export function ArtikelZeile({ item, tripId, categories, onCategoryChange: _onCa
           />
         )}
 
-        <button onClick={() => setEditing(true)} title={t('common.rename')} style={{ background: 'none', border: 'none', cursor: 'pointer', padding: '3px 4px', borderRadius: 6, display: 'flex', color: 'var(--text-faint)' }}
+        <button type="button" onClick={() => setEditing(true)} title={t('common.rename')} style={{ background: 'none', border: 'none', cursor: 'pointer', padding: '3px 4px', borderRadius: 6, display: 'flex', color: 'var(--text-faint)' }}
           onMouseEnter={e => e.currentTarget.style.color = 'var(--text-secondary)'} onMouseLeave={e => e.currentTarget.style.color = 'var(--text-faint)'}>
           <Pencil size={13} />
         </button>
 
-        <button onClick={handleDelete} title={t('common.delete')} style={{ background: 'none', border: 'none', cursor: 'pointer', padding: '3px 4px', borderRadius: 6, display: 'flex', color: 'var(--text-faint)' }}
+        <button type="button" onClick={handleDelete} title={t('common.delete')} style={{ background: 'none', border: 'none', cursor: 'pointer', padding: '3px 4px', borderRadius: 6, display: 'flex', color: 'var(--text-faint)' }}
           onMouseEnter={e => e.currentTarget.style.color = '#ef4444'} onMouseLeave={e => e.currentTarget.style.color = 'var(--text-faint)'}>
           <Trash2 size={13} />
         </button>
@@ -344,7 +344,7 @@ export function ArtikelZeile({ item, tripId, categories, onCategoryChange: _onCa
 
       {canEdit && (
         <div className="packing-row-overflow" style={{ display: 'none', flexShrink: 0, position: 'relative' }}>
-          <button
+          <button type="button"
             ref={itemMenuBtnRef}
             onClick={() => setShowItemMenu(m => !m)}
             title={t('common.showMore')}
@@ -386,7 +386,7 @@ export function ArtikelZeile({ item, tripId, categories, onCategoryChange: _onCa
                             value={item.weight_grams ?? ''}
                             readOnly={!canEdit}
                             onValueChange={async raw => {
-                              const v = raw === '' ? null : parseInt(raw)
+                              const v = raw === '' ? null : Number.parseInt(raw)
                               try { await updatePackingItem(tripId, item.id, { weight_grams: v }) } catch { toast.error(t('packing.toast.saveError')) }
                             }}
                             placeholder="—"
@@ -459,7 +459,7 @@ interface OverflowMenuItemProps {
 
 function OverflowMenuItem({ icon, label, onClick, active = false, danger = false }: OverflowMenuItemProps) {
   return (
-    <button
+    <button type="button"
       onClick={onClick}
       style={{
         display: 'flex', alignItems: 'center', gap: 8, width: '100%',
diff --git a/client/src/components/Packing/PackingShareControl.tsx b/client/src/components/Packing/PackingShareControl.tsx
index ae65262ec..0eb85d93d 100644
--- a/client/src/components/Packing/PackingShareControl.tsx
+++ b/client/src/components/Packing/PackingShareControl.tsx
@@ -49,7 +49,7 @@ export default function PackingShareControl({ item, tripMembers, currentUserId,
   }
 
   const btn = (onClick: () => void, title: string, active: boolean, node: React.ReactNode) => (
-    <button onClick={onClick} title={title}
+    <button type="button" onClick={onClick} title={title}
       style={{ background: 'none', border: 'none', cursor: 'pointer', padding: '3px 4px', borderRadius: 6, display: 'flex', color: active ? 'var(--accent)' : 'var(--text-faint)' }}
       onMouseEnter={e => { if (!active) e.currentTarget.style.color = 'var(--text-secondary)' }}
       onMouseLeave={e => { if (!active) e.currentTarget.style.color = 'var(--text-faint)' }}>
@@ -72,7 +72,7 @@ export default function PackingShareControl({ item, tripMembers, currentUserId,
 
   return (
     <div style={{ display: 'flex' }}>
-      <button ref={btnRef} onClick={toggle} title={t('packing.share')}
+      <button type="button" ref={btnRef} onClick={toggle} title={t('packing.share')}
         style={{ background: 'none', border: 'none', cursor: 'pointer', padding: '3px 4px', borderRadius: 6, display: 'flex', color: visibility !== 'common' ? 'var(--accent)' : 'var(--text-faint)' }}
         onMouseEnter={e => { if (visibility === 'common') e.currentTarget.style.color = 'var(--text-secondary)' }}
         onMouseLeave={e => { if (visibility === 'common') e.currentTarget.style.color = 'var(--text-faint)' }}>
@@ -97,7 +97,7 @@ export default function PackingShareControl({ item, tripMembers, currentUserId,
             ) : others.map(m => {
               const on = recipientIds.includes(m.id)
               return (
-                <button key={m.id} onClick={() => toggleRecipient(m.id)}
+                <button type="button" key={m.id} onClick={() => toggleRecipient(m.id)}
                   style={{ display: 'flex', alignItems: 'center', gap: 8, width: '100%', padding: '6px 10px', borderRadius: 7, border: 'none', cursor: 'pointer', background: 'none', fontFamily: 'inherit', fontSize: 'calc(12px * var(--fs-scale-body, 1))', color: 'var(--text-primary)' }}
                   onMouseEnter={e => e.currentTarget.style.background = 'var(--bg-tertiary)'}
                   onMouseLeave={e => e.currentTarget.style.background = 'none'}>
@@ -117,7 +117,7 @@ export default function PackingShareControl({ item, tripMembers, currentUserId,
 
 function Row({ icon, label, sub, active, onClick }: { icon: React.ReactNode; label: string; sub: string; active: boolean; onClick: () => void }) {
   return (
-    <button onClick={onClick}
+    <button type="button" onClick={onClick}
       style={{ display: 'flex', alignItems: 'flex-start', gap: 8, width: '100%', padding: '7px 10px', borderRadius: 7, border: 'none', cursor: 'pointer', background: active ? 'var(--bg-tertiary)' : 'none', fontFamily: 'inherit', textAlign: 'left' }}
       onMouseEnter={e => { if (!active) e.currentTarget.style.background = 'var(--bg-tertiary)' }}
       onMouseLeave={e => { if (!active) e.currentTarget.style.background = 'none' }}>
diff --git a/client/src/components/Planner/AirTrailImportModal.tsx b/client/src/components/Planner/AirTrailImportModal.tsx
index 8de9f228b..6e62cc86f 100644
--- a/client/src/components/Planner/AirTrailImportModal.tsx
+++ b/client/src/components/Planner/AirTrailImportModal.tsx
@@ -236,7 +236,7 @@ export default function AirTrailImportModal({ isOpen, onClose, tripId, pushUndo
     const isSelected = selected.has(f.id)
     const label = f.flightNumber ? `${f.airline ? `${f.airline} ` : ''}${f.flightNumber}` : `${f.fromCode ?? '?'} → ${f.toCode ?? '?'}`
     return (
-      <button
+      <button type="button"
         key={f.id}
         onClick={() => !already && toggle(f.id)}
         disabled={already}
@@ -279,7 +279,7 @@ export default function AirTrailImportModal({ isOpen, onClose, tripId, pushUndo
     return (
       <div key={chainKey(chain)} style={{ border: '1px solid var(--border-primary)', borderRadius: 12, padding: '8px 8px 0', marginBottom: 8 }}>
         {chain.map(renderFlight)}
-        <button
+        <button type="button"
           onClick={() => toggleJoin(chain)}
           className="bg-transparent"
           style={{
@@ -327,7 +327,7 @@ export default function AirTrailImportModal({ isOpen, onClose, tripId, pushUndo
           <div style={{ flex: 1, fontSize: 'calc(15px * var(--fs-scale-subtitle, 1))', fontWeight: 700, color: 'var(--text-primary)' }}>
             {t('reservations.airtrail.title')}
           </div>
-          <button onClick={handleClose} className="bg-transparent text-content-faint" style={{ border: 'none', cursor: 'pointer', padding: 4, borderRadius: 6, display: 'flex', alignItems: 'center' }}>
+          <button type="button" onClick={handleClose} className="bg-transparent text-content-faint" style={{ border: 'none', cursor: 'pointer', padding: 4, borderRadius: 6, display: 'flex', alignItems: 'center' }}>
             <X size={16} />
           </button>
         </div>
@@ -371,13 +371,13 @@ export default function AirTrailImportModal({ isOpen, onClose, tripId, pushUndo
         </div>
 
         <div style={{ display: 'flex', gap: 8, justifyContent: 'flex-end', marginTop: 14, paddingTop: 14, borderTop: '1px solid var(--border-faint)' }}>
-          <button
+          <button type="button"
             onClick={handleClose}
             style={{ padding: '8px 16px', borderRadius: 10, border: '1px solid var(--border-primary)', background: 'none', color: 'var(--text-primary)', fontSize: 'calc(13px * var(--fs-scale-body, 1))', fontWeight: 500, cursor: 'pointer', fontFamily: 'inherit' }}
           >
             {t('common.cancel')}
           </button>
-          <button
+          <button type="button"
             onClick={handleImport}
             disabled={selectableCount === 0 || importing}
             className={selectableCount > 0 && !importing ? 'bg-accent text-accent-text' : 'bg-surface-tertiary text-content-faint'}
diff --git a/client/src/components/Planner/BookingImportModal.tsx b/client/src/components/Planner/BookingImportModal.tsx
index 1def5b3ae..687c4b5d4 100644
--- a/client/src/components/Planner/BookingImportModal.tsx
+++ b/client/src/components/Planner/BookingImportModal.tsx
@@ -130,7 +130,7 @@ export default function BookingImportModal({ isOpen, onClose, tripId }: BookingI
           <div style={{ flex: 1, fontSize: 'calc(15px * var(--fs-scale-subtitle, 1))', fontWeight: 700, color: 'var(--text-primary)' }}>
             {t('reservations.import.title')}
           </div>
-          <button onClick={handleClose} className="bg-transparent text-content-faint" style={{ border: 'none', cursor: 'pointer', padding: 4, borderRadius: 6, display: 'flex', alignItems: 'center' }}>
+          <button type="button" onClick={handleClose} className="bg-transparent text-content-faint" style={{ border: 'none', cursor: 'pointer', padding: 4, borderRadius: 6, display: 'flex', alignItems: 'center' }}>
             <X size={16} />
           </button>
         </div>
@@ -184,13 +184,13 @@ export default function BookingImportModal({ isOpen, onClose, tripId }: BookingI
 
         {/* Footer */}
         <div style={{ display: 'flex', gap: 8, justifyContent: 'flex-end', marginTop: 14, paddingTop: 14, borderTop: '1px solid var(--border-faint)' }}>
-          <button
+          <button type="button"
             onClick={handleClose}
             style={{ padding: '8px 16px', borderRadius: 10, border: '1px solid var(--border-primary)', background: 'none', color: 'var(--text-primary)', fontSize: 'calc(13px * var(--fs-scale-body, 1))', fontWeight: 500, cursor: 'pointer', fontFamily: 'inherit' }}
           >
             {t('common.cancel')}
           </button>
-          <button
+          <button type="button"
             onClick={handleParse}
             disabled={files.length === 0 || loading}
             className={files.length > 0 && !loading ? 'bg-accent text-accent-text' : 'bg-surface-tertiary text-content-faint'}
diff --git a/client/src/components/Planner/DayDetailPanel.tsx b/client/src/components/Planner/DayDetailPanel.tsx
index 39eabef90..4e6573885 100644
--- a/client/src/components/Planner/DayDetailPanel.tsx
+++ b/client/src/components/Planner/DayDetailPanel.tsx
@@ -174,7 +174,7 @@ export default function DayDetailPanel({ day, days, places, categories = [], tri
                   {day.title || t('planner.dayN', { n: (days.indexOf(day) + 1) || '?' })}
                 </span>
                 {canEditDays && onUpdateDayTitle && (
-                  <button onClick={startRename} aria-label={t('common.edit')} title={t('common.edit')} className="text-content-faint" style={{ border: 'none', background: 'none', padding: 3, cursor: 'pointer', display: 'flex', flexShrink: 0 }}>
+                  <button type="button" onClick={startRename} aria-label={t('common.edit')} title={t('common.edit')} className="text-content-faint" style={{ border: 'none', background: 'none', padding: 3, cursor: 'pointer', display: 'flex', flexShrink: 0 }}>
                     <Pencil size={12} strokeWidth={1.8} />
                   </button>
                 )}
@@ -182,14 +182,14 @@ export default function DayDetailPanel({ day, days, places, categories = [], tri
             )}
             {!collapsed && formattedDate && <div className="text-content-muted" style={{ fontSize: 'calc(12px * var(--fs-scale-body, 1))', marginTop: 1 }}>{formattedDate}</div>}
           </div>
-          <button onClick={(e) => { e.stopPropagation(); toggleCollapse() }} title={collapsed ? t('common.expand') : t('common.collapse')}
+          <button type="button" onClick={(e) => { e.stopPropagation(); toggleCollapse() }} title={collapsed ? t('common.expand') : t('common.collapse')}
             className="bg-surface-secondary"
             style={{ border: 'none', borderRadius: 10, width: 32, height: 32, display: 'flex', alignItems: 'center', justifyContent: 'center', cursor: 'pointer', flexShrink: 0, transition: 'all 0.15s ease' }}
             onMouseEnter={e => e.currentTarget.style.background = 'var(--bg-hover)'}
             onMouseLeave={e => e.currentTarget.style.background = 'var(--bg-secondary)'}>
             {collapsed ? <ChevronsUp size={14} className="text-content-muted" /> : <ChevronsDown size={14} className="text-content-muted" />}
           </button>
-          <button onClick={(e) => { e.stopPropagation(); onClose() }} className="bg-surface-secondary" style={{ border: 'none', borderRadius: 10, width: 32, height: 32, display: 'flex', alignItems: 'center', justifyContent: 'center', cursor: 'pointer', flexShrink: 0 }}
+          <button type="button" onClick={(e) => { e.stopPropagation(); onClose() }} className="bg-surface-secondary" style={{ border: 'none', borderRadius: 10, width: 32, height: 32, display: 'flex', alignItems: 'center', justifyContent: 'center', cursor: 'pointer', flexShrink: 0 }}
             onMouseEnter={e => e.currentTarget.style.background = 'var(--bg-hover)'}
             onMouseLeave={e => e.currentTarget.style.background = 'var(--bg-secondary)'}>
             <X size={14} className="text-content-muted" />
@@ -409,11 +409,11 @@ function AccommodationList({ dayAccommodations, day, reservations, canEditDays,
                           <div style={{ fontSize: 'calc(13px * var(--fs-scale-body, 1))', fontWeight: 600, color: 'var(--text-primary)', overflow: 'hidden', textOverflow: 'ellipsis', whiteSpace: 'nowrap' }}>{acc.place_name}</div>
                           {acc.place_address && <div style={{ fontSize: 'calc(10px * var(--fs-scale-caption, 1))', color: 'var(--text-faint)', overflow: 'hidden', textOverflow: 'ellipsis', whiteSpace: 'nowrap' }}>{acc.place_address}</div>}
                         </div>
-                        {canEditDays && <button onClick={() => { setAccommodation(acc); setHotelForm({ check_in: acc.check_in || '', check_in_end: acc.check_in_end || '', check_out: acc.check_out || '', confirmation: acc.confirmation || '', place_id: acc.place_id }); setHotelDayRange({ start: acc.start_day_id, end: acc.end_day_id }); setShowHotelPicker('edit') }}
+                        {canEditDays && <button type="button" onClick={() => { setAccommodation(acc); setHotelForm({ check_in: acc.check_in || '', check_in_end: acc.check_in_end || '', check_out: acc.check_out || '', confirmation: acc.confirmation || '', place_id: acc.place_id }); setHotelDayRange({ start: acc.start_day_id, end: acc.end_day_id }); setShowHotelPicker('edit') }}
                           style={{ background: 'none', border: 'none', cursor: 'pointer', padding: 3, flexShrink: 0 }}>
                           <Pencil size={12} style={{ color: 'var(--text-faint)' }} />
                         </button>}
-                        {canEditDays && <button onClick={() => { setAccommodation(acc); handleRemoveAccommodation() }} style={{ background: 'none', border: 'none', cursor: 'pointer', padding: 3, flexShrink: 0 }}>
+                        {canEditDays && <button type="button" onClick={() => { setAccommodation(acc); handleRemoveAccommodation() }} style={{ background: 'none', border: 'none', cursor: 'pointer', padding: 3, flexShrink: 0 }}>
                           <X size={12} style={{ color: 'var(--text-faint)' }} />
                         </button>}
                       </div>
@@ -468,7 +468,7 @@ function AccommodationList({ dayAccommodations, day, reservations, canEditDays,
                   )
                 })}
                 {/* Add another hotel */}
-                {canEditDays && <button onClick={() => setShowHotelPicker(true)} style={{
+                {canEditDays && <button type="button" onClick={() => setShowHotelPicker(true)} style={{
                   width: '100%', padding: 8, border: '1.5px dashed var(--border-primary)', borderRadius: 10,
                   background: 'none', cursor: 'pointer', display: 'flex', alignItems: 'center', justifyContent: 'center', gap: 5,
                   fontSize: 'calc(10px * var(--fs-scale-caption, 1))', color: 'var(--text-faint)', fontFamily: 'inherit',
@@ -477,7 +477,7 @@ function AccommodationList({ dayAccommodations, day, reservations, canEditDays,
                 </button>}
               </div>
             ) : (
-              canEditDays ? <button onClick={() => setShowHotelPicker(true)} style={{
+              canEditDays ? <button type="button" onClick={() => setShowHotelPicker(true)} style={{
                 width: '100%', padding: 10, border: '1.5px dashed var(--border-primary)', borderRadius: 10,
                 background: 'none', cursor: 'pointer', display: 'flex', alignItems: 'center', justifyContent: 'center', gap: 5,
                 fontSize: 'calc(11px * var(--fs-scale-caption, 1))', color: 'var(--text-faint)', fontFamily: 'inherit',
@@ -546,7 +546,7 @@ function HotelPickerModal({ showHotelPicker, setShowHotelPicker, font, t, hotelD
                   <div style={{ padding: '16px 18px 12px', borderBottom: '1px solid var(--border-faint)', display: 'flex', alignItems: 'center', gap: 10 }}>
                     <Hotel size={16} style={{ color: 'var(--text-primary)' }} />
                     <span style={{ fontSize: 'calc(14px * var(--fs-scale-body, 1))', fontWeight: 700, color: 'var(--text-primary)', flex: 1 }}>{showHotelPicker === 'edit' ? t('day.editAccommodation') : t('day.addAccommodation')}</span>
-                    <button onClick={() => setShowHotelPicker(false)} style={{ background: 'var(--bg-secondary)', border: 'none', borderRadius: 8, width: 28, height: 28, display: 'flex', alignItems: 'center', justifyContent: 'center', cursor: 'pointer' }}>
+                    <button type="button" onClick={() => setShowHotelPicker(false)} style={{ background: 'var(--bg-secondary)', border: 'none', borderRadius: 8, width: 28, height: 28, display: 'flex', alignItems: 'center', justifyContent: 'center', cursor: 'pointer' }}>
                       <X size={12} style={{ color: 'var(--text-muted)' }} />
                     </button>
                   </div>
@@ -584,7 +584,7 @@ function HotelPickerModal({ showHotelPicker, setShowHotelPicker, font, t, hotelD
                           size="sm"
                         />
                       </div>
-                      <button onClick={() => setHotelDayRange({ start: days[0]?.id, end: days[days.length - 1]?.id })} style={{
+                      <button type="button" onClick={() => setHotelDayRange({ start: days[0]?.id, end: days[days.length - 1]?.id })} style={{
                         padding: '6px 14px', borderRadius: 8, border: 'none', fontSize: 'calc(11px * var(--fs-scale-caption, 1))', fontWeight: 600, cursor: 'pointer', flexShrink: 0,
                         background: hotelDayRange.start === days[0]?.id && hotelDayRange.end === days[days.length - 1]?.id ? 'var(--text-primary)' : 'var(--bg-card)',
                         color: hotelDayRange.start === days[0]?.id && hotelDayRange.end === days[days.length - 1]?.id ? 'var(--bg-card)' : 'var(--text-muted)',
@@ -618,14 +618,14 @@ function HotelPickerModal({ showHotelPicker, setShowHotelPicker, font, t, hotelD
                   {/* Category Filter */}
                   {categories.length > 0 && (
                     <div style={{ padding: '8px 18px', borderBottom: '1px solid var(--border-faint)', display: 'flex', gap: 4, flexWrap: 'wrap' }}>
-                      <button onClick={() => setHotelCategoryFilter('')} style={{
+                      <button type="button" onClick={() => setHotelCategoryFilter('')} style={{
                         padding: '3px 10px', borderRadius: 6, border: 'none', fontSize: 'calc(10px * var(--fs-scale-caption, 1))', fontWeight: 600, cursor: 'pointer',
                         background: !hotelCategoryFilter ? 'var(--text-primary)' : 'var(--bg-secondary)',
                         color: !hotelCategoryFilter ? 'var(--bg-card)' : 'var(--text-muted)',
                       }}>{t('day.allDays')}</button>
 
                       {categories.map(c => (
-                        <button key={c.id} onClick={() => setHotelCategoryFilter(c.id)} style={{
+                        <button type="button" key={c.id} onClick={() => setHotelCategoryFilter(c.id)} style={{
                           padding: '3px 10px', borderRadius: 6, border: 'none', fontSize: 'calc(10px * var(--fs-scale-caption, 1))', fontWeight: 600, cursor: 'pointer',
                           background: hotelCategoryFilter === c.id ? c.color || 'var(--text-primary)' : 'var(--bg-secondary)',
                           color: hotelCategoryFilter === c.id ? '#fff' : 'var(--text-muted)',
@@ -641,7 +641,7 @@ function HotelPickerModal({ showHotelPicker, setShowHotelPicker, font, t, hotelD
                       return filtered.length === 0 ? (
                         <div style={{ padding: 20, textAlign: 'center', fontSize: 'calc(12px * var(--fs-scale-body, 1))', color: 'var(--text-faint)' }}>{t('day.noPlacesForHotel')}</div>
                       ) : filtered.map(p => (
-                      <button key={p.id} onClick={() => handleSelectPlace(p.id)} style={{
+                      <button type="button" key={p.id} onClick={() => handleSelectPlace(p.id)} style={{
                         display: 'flex', alignItems: 'center', gap: 10, width: '100%', padding: '10px 18px',
                         border: 'none', borderBottom: '1px solid var(--border-faint)',
                         background: hotelForm.place_id === p.id ? 'var(--bg-hover)' : 'none',
@@ -671,10 +671,10 @@ function HotelPickerModal({ showHotelPicker, setShowHotelPicker, font, t, hotelD
 
                 {/* Save / Cancel */}
                 <div style={{ padding: '12px 18px', borderTop: '1px solid var(--border-faint)', display: 'flex', justifyContent: 'flex-end', gap: 8 }}>
-                  <button onClick={() => setShowHotelPicker(false)} style={{ padding: '7px 16px', borderRadius: 8, border: '1px solid var(--border-primary)', background: 'none', fontSize: 'calc(12px * var(--fs-scale-body, 1))', cursor: 'pointer', fontFamily: 'inherit', color: 'var(--text-muted)' }}>
+                  <button type="button" onClick={() => setShowHotelPicker(false)} style={{ padding: '7px 16px', borderRadius: 8, border: '1px solid var(--border-primary)', background: 'none', fontSize: 'calc(12px * var(--fs-scale-body, 1))', cursor: 'pointer', fontFamily: 'inherit', color: 'var(--text-muted)' }}>
                     {t('common.cancel')}
                   </button>
-                  <button onClick={() => { void saveHotelPicker() }} disabled={!hotelForm.place_id} style={{
+                  <button type="button" onClick={() => { void saveHotelPicker() }} disabled={!hotelForm.place_id} style={{
                     padding: '7px 20px', borderRadius: 8, border: 'none', fontSize: 'calc(12px * var(--fs-scale-body, 1))', fontWeight: 600, cursor: 'pointer', fontFamily: 'inherit',
                     background: hotelForm.place_id ? 'var(--text-primary)' : 'var(--bg-tertiary)',
                     color: hotelForm.place_id ? 'var(--bg-card)' : 'var(--text-faint)',
diff --git a/client/src/components/Planner/DayPlanSidebar.tsx b/client/src/components/Planner/DayPlanSidebar.tsx
index 768af3397..2ce0f5d74 100644
--- a/client/src/components/Planner/DayPlanSidebar.tsx
+++ b/client/src/components/Planner/DayPlanSidebar.tsx
@@ -306,7 +306,7 @@ function useDayPlanSidebar(props: DayPlanSidebarProps) {
         assignmentId: dragDataRef.current.assignmentId || '',
         noteId: dragDataRef.current.noteId || '',
         reservationId: dragDataRef.current.reservationId || '',
-        fromDayId: parseInt(dragDataRef.current.fromDayId) || 0,
+        fromDayId: Number.parseInt(dragDataRef.current.fromDayId) || 0,
         phase: (dragDataRef.current.phase || 'single') as 'single' | 'start' | 'middle' | 'end',
       }
     }
@@ -990,7 +990,7 @@ function useDayPlanSidebar(props: DayPlanSidebarProps) {
       setDraggingId(null); setDropTargetKey(null); dragDataRef.current = null; window.__dragData = null; return
     }
     if (placeId) {
-      onAssignToDay?.(parseInt(placeId), dayId)
+      onAssignToDay?.(Number.parseInt(placeId), dayId)
     } else if (assignmentId && fromDayId !== dayId) {
       const srcAssignment = (useTripStore.getState().assignments[String(fromDayId)] || []).find(a => a.id === Number(assignmentId))
       const capturedFromDayId = fromDayId
@@ -1739,7 +1739,7 @@ const DayPlanSidebar = React.memo(function DayPlanSidebar(props: DayPlanSidebarP
                     )
                   })()
                 ) : (
-                  <button onClick={e => toggleDay(day.id, e)} className="text-content-faint" style={{ alignSelf: 'flex-start', flexShrink: 0, background: 'none', border: 'none', padding: 6, cursor: 'pointer', display: 'flex', alignItems: 'center' }}>
+                  <button type="button" onClick={e => toggleDay(day.id, e)} className="text-content-faint" style={{ alignSelf: 'flex-start', flexShrink: 0, background: 'none', border: 'none', padding: 6, cursor: 'pointer', display: 'flex', alignItems: 'center' }}>
                     {isExpanded ? <ChevronDown size={16} strokeWidth={1.8} /> : <ChevronRight size={16} strokeWidth={1.8} />}
                   </button>
                 )}
@@ -1765,7 +1765,7 @@ const DayPlanSidebar = React.memo(function DayPlanSidebar(props: DayPlanSidebarP
                       const toLegIndex = legPart ? Number(legPart.slice(3)) : null
 
                       if (placeId) {
-                        onAssignToDay?.(parseInt(placeId), day.id)
+                        onAssignToDay?.(Number.parseInt(placeId), day.id)
                       } else if (fromReservationId && fromDayId !== day.id) {
                         const r = reservations.find(x => x.id === Number(fromReservationId))
                         if (r) { const update = computeMultiDayMove(r, day.id, phase); tripActions.updateReservation(tripId, r.id, update).catch((err: unknown) => toast.error(err instanceof Error ? err.message : t('common.unknownError'))) }
@@ -1791,7 +1791,7 @@ const DayPlanSidebar = React.memo(function DayPlanSidebar(props: DayPlanSidebarP
                     }
                     if (!assignmentId && !noteId && !placeId) { dragDataRef.current = null; window.__dragData = null; return }
                     if (placeId) {
-                      onAssignToDay?.(parseInt(placeId), day.id)
+                      onAssignToDay?.(Number.parseInt(placeId), day.id)
                       setDropTargetKey(null); window.__dragData = null; return
                     }
                     if (assignmentId && fromDayId !== day.id) {
@@ -1909,7 +1909,7 @@ const DayPlanSidebar = React.memo(function DayPlanSidebar(props: DayPlanSidebarP
                               const { placeId, assignmentId: fromAssignmentId, noteId, reservationId: fromReservationId, fromDayId, phase } = getDragData(e)
                               if (placeId) {
                                 const pos = placeItems.findIndex(i => i.data.id === assignment.id)
-                                onAssignToDay?.(parseInt(placeId), day.id, pos >= 0 ? pos : undefined)
+                                onAssignToDay?.(Number.parseInt(placeId), day.id, pos >= 0 ? pos : undefined)
                                 setDropTargetKey(null); window.__dragData = null
                               } else if (fromReservationId && fromDayId !== day.id) {
                                 const r = reservations.find(x => x.id === Number(fromReservationId))
@@ -2154,15 +2154,15 @@ const DayPlanSidebar = React.memo(function DayPlanSidebar(props: DayPlanSidebarP
                               )}
                             </div>
                             {canEditDays && <div className="reorder-buttons" style={{ flexShrink: 0, display: 'flex', gap: 1, transition: 'opacity 0.15s' }}>
-                              <button onClick={moveUp} disabled={idx === 0} className={idx === 0 ? 'text-[var(--border-primary)]' : 'text-content-faint'} style={{ background: 'none', border: 'none', padding: '1px 2px', cursor: idx === 0 ? 'default' : 'pointer', display: 'flex', lineHeight: 1 }}>
+                              <button type="button" onClick={moveUp} disabled={idx === 0} className={idx === 0 ? 'text-[var(--border-primary)]' : 'text-content-faint'} style={{ background: 'none', border: 'none', padding: '1px 2px', cursor: idx === 0 ? 'default' : 'pointer', display: 'flex', lineHeight: 1 }}>
                                 <ChevronUp size={12} strokeWidth={2} />
                               </button>
-                              <button onClick={moveDown} disabled={idx === merged.length - 1} className={idx === merged.length - 1 ? 'text-[var(--border-primary)]' : 'text-content-faint'} style={{ background: 'none', border: 'none', padding: '1px 2px', cursor: idx === merged.length - 1 ? 'default' : 'pointer', display: 'flex', lineHeight: 1 }}>
+                              <button type="button" onClick={moveDown} disabled={idx === merged.length - 1} className={idx === merged.length - 1 ? 'text-[var(--border-primary)]' : 'text-content-faint'} style={{ background: 'none', border: 'none', padding: '1px 2px', cursor: idx === merged.length - 1 ? 'default' : 'pointer', display: 'flex', lineHeight: 1 }}>
                                 <ChevronDown size={12} strokeWidth={2} />
                               </button>
                             </div>}
                             {canEditDays && onAddBookingToAssignment && hoveredAssignmentId === assignment.id && (
-                              <button
+                              <button type="button"
                                 onClick={e => {
                                   e.stopPropagation()
                                   onAddBookingToAssignment(day.id, assignment.id)
@@ -2289,7 +2289,7 @@ const DayPlanSidebar = React.memo(function DayPlanSidebar(props: DayPlanSidebarP
                               const insertAfter = e.clientY > rect.top + rect.height / 2
                               const { placeId, assignmentId: fromAssignmentId, noteId, reservationId: fromReservationId, fromDayId, phase } = getDragData(e)
                               if (placeId) {
-                                onAssignToDay?.(parseInt(placeId), day.id)
+                                onAssignToDay?.(Number.parseInt(placeId), day.id)
                               } else if (fromReservationId && fromDayId !== day.id) {
                                 const r2 = reservations.find(x => x.id === Number(fromReservationId))
                                 if (r2) { const update = computeMultiDayMove(r2, day.id, phase); tripActions.updateReservation(tripId, r2.id, update).catch((err: unknown) => toast.error(err instanceof Error ? err.message : t('common.unknownError'))) }
@@ -2464,7 +2464,7 @@ const DayPlanSidebar = React.memo(function DayPlanSidebar(props: DayPlanSidebarP
                               const tm = getMergedItems(day.id)
                               const noteIdx = tm.findIndex(i => i.type === 'note' && i.data.id === note.id)
                               const pos = tm.slice(0, noteIdx).filter(i => i.type === 'place').length
-                              onAssignToDay?.(parseInt(placeId), day.id, pos)
+                              onAssignToDay?.(Number.parseInt(placeId), day.id, pos)
                               setDropTargetKey(null); window.__dragData = null
                             } else if (fromReservationId && fromDayId !== day.id) {
                               const r = reservations.find(x => x.id === Number(fromReservationId))
@@ -2549,12 +2549,12 @@ const DayPlanSidebar = React.memo(function DayPlanSidebar(props: DayPlanSidebarP
                             every note a shorter line for the whole time you are
                             not hovering. */}
                         {canEditDays && <div className="note-edit-buttons bg-surface-card" style={{ position: 'absolute', right: 5, top: '50%', transform: 'translateY(-50%)', display: 'flex', flexDirection: 'column', justifyContent: 'center', gap: 3, padding: 4, borderRadius: 999, border: '1px solid var(--border-faint)', boxShadow: '0 4px 14px rgba(0,0,0,0.10)', opacity: 0, transition: 'opacity 0.15s' }}>
-                          <button onClick={e => openEditNote(day.id, note, e)} aria-label={t('dayplan.noteEdit')} title={t('dayplan.noteEdit')} className="text-content-faint note-edit-btn" style={{ background: 'none', border: 'none', width: 30, height: 30, borderRadius: 999, cursor: 'pointer', display: 'grid', placeItems: 'center', padding: 0 }}><Pencil size={15} /></button>
-                          <button onClick={e => { e.stopPropagation(); setPendingDeleteNote({ dayId: day.id, noteId: note.id }) }} aria-label={t('dayplan.noteDelete')} title={t('dayplan.noteDelete')} className="text-content-faint note-edit-btn note-edit-btn-danger" style={{ background: 'none', border: 'none', width: 30, height: 30, borderRadius: 999, cursor: 'pointer', display: 'grid', placeItems: 'center', padding: 0 }}><Trash2 size={15} /></button>
+                          <button type="button" onClick={e => openEditNote(day.id, note, e)} aria-label={t('dayplan.noteEdit')} title={t('dayplan.noteEdit')} className="text-content-faint note-edit-btn" style={{ background: 'none', border: 'none', width: 30, height: 30, borderRadius: 999, cursor: 'pointer', display: 'grid', placeItems: 'center', padding: 0 }}><Pencil size={15} /></button>
+                          <button type="button" onClick={e => { e.stopPropagation(); setPendingDeleteNote({ dayId: day.id, noteId: note.id }) }} aria-label={t('dayplan.noteDelete')} title={t('dayplan.noteDelete')} className="text-content-faint note-edit-btn note-edit-btn-danger" style={{ background: 'none', border: 'none', width: 30, height: 30, borderRadius: 999, cursor: 'pointer', display: 'grid', placeItems: 'center', padding: 0 }}><Trash2 size={15} /></button>
                         </div>}
                         {canEditDays && <div className="reorder-buttons" style={{ flexShrink: 0, display: 'flex', gap: 1, transition: 'opacity 0.15s' }}>
-                          <button onClick={e => { e.stopPropagation(); moveNote(day.id, note.id, 'up') }} disabled={noteIdx === 0} className={noteIdx === 0 ? 'text-[var(--border-primary)]' : 'text-content-faint'} style={{ background: 'none', border: 'none', padding: '1px 2px', cursor: noteIdx === 0 ? 'default' : 'pointer', display: 'flex', lineHeight: 1 }}><ChevronUp size={12} strokeWidth={2} /></button>
-                          <button onClick={e => { e.stopPropagation(); moveNote(day.id, note.id, 'down') }} disabled={noteIdx === merged.length - 1} className={noteIdx === merged.length - 1 ? 'text-[var(--border-primary)]' : 'text-content-faint'} style={{ background: 'none', border: 'none', padding: '1px 2px', cursor: noteIdx === merged.length - 1 ? 'default' : 'pointer', display: 'flex', lineHeight: 1 }}><ChevronDown size={12} strokeWidth={2} /></button>
+                          <button type="button" onClick={e => { e.stopPropagation(); moveNote(day.id, note.id, 'up') }} disabled={noteIdx === 0} className={noteIdx === 0 ? 'text-[var(--border-primary)]' : 'text-content-faint'} style={{ background: 'none', border: 'none', padding: '1px 2px', cursor: noteIdx === 0 ? 'default' : 'pointer', display: 'flex', lineHeight: 1 }}><ChevronUp size={12} strokeWidth={2} /></button>
+                          <button type="button" onClick={e => { e.stopPropagation(); moveNote(day.id, note.id, 'down') }} disabled={noteIdx === merged.length - 1} className={noteIdx === merged.length - 1 ? 'text-[var(--border-primary)]' : 'text-content-faint'} style={{ background: 'none', border: 'none', padding: '1px 2px', cursor: noteIdx === merged.length - 1 ? 'default' : 'pointer', display: 'flex', lineHeight: 1 }}><ChevronDown size={12} strokeWidth={2} /></button>
                         </div>}
                         </div>
                         </React.Fragment>
@@ -2580,7 +2580,7 @@ const DayPlanSidebar = React.memo(function DayPlanSidebar(props: DayPlanSidebarP
                       const { placeId, assignmentId, noteId, reservationId: fromReservationId, fromDayId, phase } = getDragData(e)
                       // Neuer Ort von der Orte-Liste
                       if (placeId) {
-                        onAssignToDay?.(parseInt(placeId), day.id)
+                        onAssignToDay?.(Number.parseInt(placeId), day.id)
                         setDropTargetKey(null); window.__dragData = null; return
                       }
                       if (fromReservationId && fromDayId !== day.id) {
@@ -2618,7 +2618,7 @@ const DayPlanSidebar = React.memo(function DayPlanSidebar(props: DayPlanSidebarP
                   {(isSelected || (showRouteToolsWhenExpanded && isExpanded)) && routeToolsRoutable && (
                     <div style={{ padding: '10px 16px 12px', borderTop: '1px solid var(--border-faint)', display: 'flex', flexDirection: 'column', gap: 7 }}>
                       <div style={{ display: 'flex', gap: 6, alignItems: 'stretch' }}>
-                        <button
+                        <button type="button"
                           onClick={() => {
                             if (showRouteToolsWhenExpanded) {
                               // Mobile: toggle this day's inline leg distances in place.
@@ -2647,7 +2647,7 @@ const DayPlanSidebar = React.memo(function DayPlanSidebar(props: DayPlanSidebarP
                           {t('dayplan.route')}
                         </button>
                         {/* Open the day's stops as a route in Google Maps (planned order). #1255 */}
-                        <button
+                        <button type="button"
                           onClick={() => {
                             const url = generateGoogleMapsUrl(dayExportStops())
                             if (url) window.open(url, '_blank', 'noopener,noreferrer')
@@ -2666,7 +2666,7 @@ const DayPlanSidebar = React.memo(function DayPlanSidebar(props: DayPlanSidebarP
                         {/* The same day, handed to CoMaps for offline navigation (#1904). The
                             day's own travel mode rides along, so the route it builds walks
                             when the plan walks. */}
-                        <button
+                        <button type="button"
                           onClick={() => {
                             const url = generateCoMapsUrl(dayExportStops(), day.default_transport_mode ?? routeProfile)
                             if (url) window.open(url, '_blank', 'noopener,noreferrer')
@@ -2688,7 +2688,7 @@ const DayPlanSidebar = React.memo(function DayPlanSidebar(props: DayPlanSidebarP
                             sat against both edges as soon as the row filled up, and
                             the row gained a button when CoMaps arrived. The label
                             stays as the accessible name and the tooltip. */}
-                        <button
+                        <button type="button"
                           onClick={() => handleOptimize(day.id)}
                           aria-label={t('dayplan.optimize')}
                           title={t('dayplan.optimize')}
@@ -2706,7 +2706,7 @@ const DayPlanSidebar = React.memo(function DayPlanSidebar(props: DayPlanSidebarP
                             const ModeIcon = p.key === 'driving' ? Car : p.key === 'walking' ? Footprints : Zap
                             const active = (day.default_transport_mode ?? routeProfile) === p.key
                             return (
-                              <button
+                              <button type="button"
                                 key={p.key}
                                 onClick={() => setDayDefaultMode(day.id, p.key)}
                                 aria-label={p.label}
diff --git a/client/src/components/Planner/DayPlanSidebarMobileAddPlaceButton.tsx b/client/src/components/Planner/DayPlanSidebarMobileAddPlaceButton.tsx
index f1ebe50ae..96f942c22 100644
--- a/client/src/components/Planner/DayPlanSidebarMobileAddPlaceButton.tsx
+++ b/client/src/components/Planner/DayPlanSidebarMobileAddPlaceButton.tsx
@@ -24,7 +24,7 @@ export function MobileAddPlaceButton({ dayId, places, assignments, onAssign, onA
   return (
     <div className="md:hidden" style={{ padding: '8px 12px 12px' }}>
       {!open ? (
-        <button
+        <button type="button"
           onClick={e => { e.stopPropagation(); setOpen(true) }}
           style={{
             width: '100%', display: 'flex', alignItems: 'center', justifyContent: 'center', gap: 6,
@@ -47,7 +47,7 @@ export function MobileAddPlaceButton({ dayId, places, assignments, onAssign, onA
               placeholder={t('dayplan.mobile.searchPlaces')}
               style={{ flex: 1, border: 'none', outline: 'none', background: 'transparent', fontSize: 'calc(13px * var(--fs-scale-body, 1))', fontFamily: 'inherit', color: 'var(--text-primary)' }}
             />
-            <button onClick={() => { setOpen(false); setSearch('') }} style={{ background: 'none', border: 'none', cursor: 'pointer', padding: 2, color: 'var(--text-faint)' }}>
+            <button type="button" onClick={() => { setOpen(false); setSearch('') }} style={{ background: 'none', border: 'none', cursor: 'pointer', padding: 2, color: 'var(--text-faint)' }}>
               <X size={14} />
             </button>
           </div>
@@ -58,7 +58,7 @@ export function MobileAddPlaceButton({ dayId, places, assignments, onAssign, onA
               </div>
             )}
             {filtered.slice(0, 20).map(p => (
-              <button
+              <button type="button"
                 key={p.id}
                 onClick={() => {
                   onAssign?.(p.id, dayId)
@@ -77,7 +77,7 @@ export function MobileAddPlaceButton({ dayId, places, assignments, onAssign, onA
             ))}
           </div>
           {onAddNew && (
-            <button
+            <button type="button"
               onClick={() => { onAddNew(); setOpen(false); setSearch('') }}
               style={{
                 width: '100%', display: 'flex', alignItems: 'center', justifyContent: 'center', gap: 6,
diff --git a/client/src/components/Planner/DayPlanSidebarTimeConfirmModal.tsx b/client/src/components/Planner/DayPlanSidebarTimeConfirmModal.tsx
index 3c1bdf67c..21f207e6b 100644
--- a/client/src/components/Planner/DayPlanSidebarTimeConfirmModal.tsx
+++ b/client/src/components/Planner/DayPlanSidebarTimeConfirmModal.tsx
@@ -47,11 +47,11 @@ export function DayPlanSidebarTimeConfirmModal({ timeConfirm, setTimeConfirm, co
           {t('dayplan.confirmRemoveTimeBody', { time: timeConfirm.time })}
         </div>
         <div style={{ display: 'flex', gap: 8, justifyContent: 'flex-end', marginTop: 4 }}>
-          <button onClick={() => setTimeConfirm(null)} className="text-content-muted" style={{
+          <button type="button" onClick={() => setTimeConfirm(null)} className="text-content-muted" style={{
             fontSize: 'calc(12px * var(--fs-scale-body, 1))', background: 'none', border: '1px solid var(--border-primary)',
             borderRadius: 8, padding: '6px 14px', cursor: 'pointer', fontFamily: 'inherit',
           }}>{t('common.cancel')}</button>
-          <button onClick={confirmTimeRemoval} className="bg-[#ef4444] text-white" style={{
+          <button type="button" onClick={confirmTimeRemoval} className="bg-[#ef4444] text-white" style={{
             fontSize: 'calc(12px * var(--fs-scale-body, 1))',
             border: 'none', borderRadius: 8, padding: '6px 16px', cursor: 'pointer', fontWeight: 600, fontFamily: 'inherit',
           }}>{t('common.confirm')}</button>
diff --git a/client/src/components/Planner/DayPlanSidebarToolbar.tsx b/client/src/components/Planner/DayPlanSidebarToolbar.tsx
index e41a20b0d..94a1833ef 100644
--- a/client/src/components/Planner/DayPlanSidebarToolbar.tsx
+++ b/client/src/components/Planner/DayPlanSidebarToolbar.tsx
@@ -94,7 +94,7 @@ export function DayPlanSidebarToolbar({
           const label = allExpanded ? t('dayplan.collapseAll') : t('dayplan.expandAll')
           return (
             <Tooltip label={label} placement="bottom">
-              <button
+              <button type="button"
                 onClick={() => {
                   const next = allExpanded ? new Set<number>() : new Set(days.map(d => d.id))
                   setExpandedDays(next)
@@ -138,7 +138,7 @@ export function DayPlanSidebarToolbar({
         })()}
         {onUndo && (
           <div style={{ position: 'relative', flexShrink: 0 }}>
-            <button
+            <button type="button"
               onClick={onUndo}
               disabled={!canUndo}
               aria-label={t('undo.button')}
@@ -172,7 +172,7 @@ export function DayPlanSidebarToolbar({
         {canEditDays && onReorderDays && onAddDay && days.length > 0 && (
           <div style={{ position: 'relative', flexShrink: 0 }}>
             <Tooltip label={t('dayplan.reorderDays')} placement="bottom">
-              <button
+              <button type="button"
                 onClick={() => setReorderOpen(v => !v)}
                 aria-label={t('dayplan.reorderDays')}
                 aria-pressed={reorderOpen}
diff --git a/client/src/components/Planner/DayPlanSidebarTransportDetailModal.tsx b/client/src/components/Planner/DayPlanSidebarTransportDetailModal.tsx
index 84d98f3ee..3df43e116 100644
--- a/client/src/components/Planner/DayPlanSidebarTransportDetailModal.tsx
+++ b/client/src/components/Planner/DayPlanSidebarTransportDetailModal.tsx
@@ -241,7 +241,7 @@ export function DayPlanSidebarTransportDetailModal({
               {/* Aktionen */}
               <div style={{ display: 'flex', justifyContent: 'flex-end', gap: 8 }}>
                 {onEdit && (
-                  <button onClick={() => onEdit(res)} className="bg-surface-tertiary text-content" style={{
+                  <button type="button" onClick={() => onEdit(res)} className="bg-surface-tertiary text-content" style={{
                     fontSize: 'calc(12px * var(--fs-scale-body, 1))',
                     border: 'none', borderRadius: 8, padding: '6px 14px', cursor: 'pointer', fontWeight: 600, fontFamily: 'inherit',
                     display: 'inline-flex', alignItems: 'center', gap: 5,
@@ -249,7 +249,7 @@ export function DayPlanSidebarTransportDetailModal({
                     <Pencil size={12} /> {t('common.edit')}
                   </button>
                 )}
-                <button onClick={() => setTransportDetail(null)} className="bg-accent text-accent-text" style={{
+                <button type="button" onClick={() => setTransportDetail(null)} className="bg-accent text-accent-text" style={{
                   fontSize: 'calc(12px * var(--fs-scale-body, 1))',
                   border: 'none', borderRadius: 8, padding: '6px 16px', cursor: 'pointer', fontWeight: 600, fontFamily: 'inherit',
                 }}>
diff --git a/client/src/components/Planner/DayReorderPopup.tsx b/client/src/components/Planner/DayReorderPopup.tsx
index d3a45b297..009f7114a 100644
--- a/client/src/components/Planner/DayReorderPopup.tsx
+++ b/client/src/components/Planner/DayReorderPopup.tsx
@@ -56,7 +56,7 @@ export function DayReorderPopup({ isOpen, days, t, locale, onReorder, onAddDay,
       size="md"
       footer={
         <div style={{ display: 'flex', alignItems: 'center', justifyContent: 'space-between', gap: 12 }}>
-          <button
+          <button type="button"
             onClick={onClose}
             style={{
               padding: '8px 16px', borderRadius: 8, fontSize: 13, fontWeight: 500,
@@ -66,7 +66,7 @@ export function DayReorderPopup({ isOpen, days, t, locale, onReorder, onAddDay,
           >
             {t('common.close')}
           </button>
-          <button
+          <button type="button"
             onClick={onAddDay}
             className="bg-accent text-accent-text"
             style={{
diff --git a/client/src/components/Planner/FileImportModal.tsx b/client/src/components/Planner/FileImportModal.tsx
index a823468af..70aaa2732 100644
--- a/client/src/components/Planner/FileImportModal.tsx
+++ b/client/src/components/Planner/FileImportModal.tsx
@@ -360,7 +360,7 @@ export default function FileImportModal({ isOpen, onClose, tripId, pushUndo, ini
         )}
 
         <div style={{ display: 'flex', gap: 8, justifyContent: 'flex-end' }}>
-          <button
+          <button type="button"
             onClick={handleClose}
             style={{
               padding: '8px 16px', borderRadius: 10, border: '1px solid var(--border-primary)',
@@ -370,7 +370,7 @@ export default function FileImportModal({ isOpen, onClose, tripId, pushUndo, ini
           >
             {t('common.cancel')}
           </button>
-          <button
+          <button type="button"
             onClick={handleImport}
             disabled={!canImport}
             className={canImport ? 'bg-accent text-accent-text' : 'bg-surface-tertiary text-content-faint'}
diff --git a/client/src/components/Planner/IcsSubscribeModal.tsx b/client/src/components/Planner/IcsSubscribeModal.tsx
index dc66002f8..b9a89fffd 100644
--- a/client/src/components/Planner/IcsSubscribeModal.tsx
+++ b/client/src/components/Planner/IcsSubscribeModal.tsx
@@ -89,7 +89,7 @@ export function IcsSubscribeModal({ endpoint, title, description, onClose }: Ics
             <Calendar size={16} strokeWidth={2} style={{ color: 'var(--accent, #6366f1)' }} />
             <span style={{ fontWeight: 600, fontSize: 14 }}>{title}</span>
           </div>
-          <button
+          <button type="button"
             onClick={onClose}
             style={{
               background: 'none', border: 'none', cursor: 'pointer', padding: 4,
@@ -110,7 +110,7 @@ export function IcsSubscribeModal({ endpoint, title, description, onClose }: Ics
           </div>
         ) : !feedUrl ? (
           <>
-            <button
+            <button type="button"
               onClick={() => mutate('POST')}
               disabled={busy}
               style={{
@@ -133,7 +133,7 @@ export function IcsSubscribeModal({ endpoint, title, description, onClose }: Ics
             <SubscribeLinks httpsUrl={httpsUrl} webcalUrl={webcalUrl} />
 
             <div style={{ marginTop: 16, paddingTop: 12, borderTop: '1px solid var(--border-faint)', display: 'flex', gap: 8 }}>
-              <button
+              <button type="button"
                 onClick={() => mutate('PUT')}
                 disabled={busy}
                 style={{
@@ -148,7 +148,7 @@ export function IcsSubscribeModal({ endpoint, title, description, onClose }: Ics
                 <RefreshCw size={11} strokeWidth={2} style={{ animation: busy ? 'spin 0.8s linear infinite' : 'none' }} />
                 Regenerate
               </button>
-              <button
+              <button type="button"
                 onClick={() => mutate('DELETE')}
                 disabled={busy}
                 style={{
diff --git a/client/src/components/Planner/PlaceFormModal.tsx b/client/src/components/Planner/PlaceFormModal.tsx
index 50f615f58..29ecd33af 100644
--- a/client/src/components/Planner/PlaceFormModal.tsx
+++ b/client/src/components/Planner/PlaceFormModal.tsx
@@ -66,8 +66,8 @@ function findDuplicatePlace(
 ): { name?: string | null } | null {
   const name = (form.name || '').trim().toLowerCase()
   const gid = (form.google_place_id || '').trim()
-  const lat = form.lat ? parseFloat(form.lat) : null
-  const lng = form.lng ? parseFloat(form.lng) : null
+  const lat = form.lat ? Number.parseFloat(form.lat) : null
+  const lng = form.lng ? Number.parseFloat(form.lng) : null
   for (const p of places || []) {
     if (gid && p.google_place_id && p.google_place_id === gid) return p
     if (name && p.name && p.name.trim().toLowerCase() === name) return p
@@ -473,8 +473,8 @@ function usePlaceFormModal(props: PlaceFormModalProps) {
     try {
       const saved = await onSave({
         ...form,
-        lat: form.lat ? parseFloat(form.lat) : null,
-        lng: form.lng ? parseFloat(form.lng) : null,
+        lat: form.lat ? Number.parseFloat(form.lat) : null,
+        lng: form.lng ? Number.parseFloat(form.lng) : null,
         category_id: form.category_id || null,
         _pendingFiles: pendingFiles.length > 0 ? pendingFiles : undefined,
       })
diff --git a/client/src/components/Planner/PlaceInspector.tsx b/client/src/components/Planner/PlaceInspector.tsx
index 663e5a9db..ef99b5f47 100644
--- a/client/src/components/Planner/PlaceInspector.tsx
+++ b/client/src/components/Planner/PlaceInspector.tsx
@@ -580,7 +580,7 @@ export function ActionButton({ onClick, variant, icon, label, ref }: ActionButto
   }
   const s = base[variant] || base.ghost
   return (
-    <button
+    <button type="button"
       ref={ref}
       onClick={onClick}
       style={{
@@ -676,7 +676,7 @@ function ParticipantsBox({ tripMembers, participantIds, allJoined, onSetParticip
         {/* Add button */}
         {availableToAdd.length > 0 && (
           <div style={{ position: 'relative' }}>
-            <button onClick={() => setShowAdd(!showAdd)} className="text-content-faint" style={{
+            <button type="button" onClick={() => setShowAdd(!showAdd)} className="text-content-faint" style={{
               width: 22, height: 22, borderRadius: '50%', border: '1.5px dashed var(--border-primary)',
               background: 'none', cursor: 'pointer', display: 'flex', alignItems: 'center', justifyContent: 'center',
               fontSize: 'calc(12px * var(--fs-scale-body, 1))', transition: 'all 0.12s',
@@ -692,7 +692,7 @@ function ParticipantsBox({ tripMembers, participantIds, allJoined, onSetParticip
                 boxShadow: '0 4px 16px rgba(0,0,0,0.12)', padding: 4, minWidth: 140,
               }}>
                 {availableToAdd.map(member => (
-                  <button key={member.id} onClick={() => handleAdd(member.id)} className="text-content" style={{
+                  <button type="button" key={member.id} onClick={() => handleAdd(member.id)} className="text-content" style={{
                     display: 'flex', alignItems: 'center', gap: 6, width: '100%', padding: '5px 8px',
                     borderRadius: 6, border: 'none', background: 'none', cursor: 'pointer',
                     fontFamily: 'inherit', fontSize: 'calc(11px * var(--fs-scale-caption, 1))', textAlign: 'left',
@@ -807,7 +807,7 @@ function PlaceInspectorHeader({ openNow, place, category, t, editingName, nameIn
               </div>
             )}
           </div>
-          <button
+          <button type="button"
             onClick={onClose}
             className="bg-surface-hover"
             style={{ width: 28, height: 28, borderRadius: '50%', border: 'none', display: 'flex', alignItems: 'center', justifyContent: 'center', cursor: 'pointer', flexShrink: 0, alignSelf: 'flex-start', transition: 'background 0.15s' }}
@@ -940,7 +940,7 @@ function TrackColorRow({ place, trackColor, onUpdatePlace, t }: any) {
   const [open, setOpen] = useState(false)
   return (
     <div className="bg-surface-hover" style={{ borderRadius: 10, padding: '10px 12px', display: 'flex', flexDirection: 'column', gap: 8 }}>
-      <button
+      <button type="button"
         onClick={() => setOpen(o => !o)}
         aria-expanded={open}
         style={{
@@ -980,7 +980,7 @@ function PlaceExtras({ openingHours, weekdayIndex, hoursExpanded, setHoursExpand
           <div className={`grid grid-cols-1 ${openingHours?.length > 0 ? 'sm:grid-cols-2' : ''} gap-2`}>
           {openingHours && openingHours.length > 0 && (
             <div className="bg-surface-hover" style={{ borderRadius: 10, overflow: 'hidden' }}>
-              <button
+              <button type="button"
                 onClick={() => setHoursExpanded(h => !h)}
                 style={{
                   width: '100%', display: 'flex', alignItems: 'center', justifyContent: 'space-between',
@@ -1111,7 +1111,7 @@ function PlaceExtras({ openingHours, weekdayIndex, hoursExpanded, setHoursExpand
           {(placeFiles.length > 0 || onFileUpload) && (
             <div className="bg-surface-hover" style={{ borderRadius: 10, overflow: 'hidden' }}>
               <div style={{ display: 'flex', alignItems: 'center', padding: '8px 12px', gap: 6 }}>
-                <button
+                <button type="button"
                   onClick={() => setFilesExpanded(f => !f)}
                   style={{ flex: 1, display: 'flex', alignItems: 'center', gap: 6, background: 'none', border: 'none', cursor: 'pointer', padding: 0, fontFamily: 'inherit', textAlign: 'left' }}
                 >
@@ -1135,7 +1135,7 @@ function PlaceExtras({ openingHours, weekdayIndex, hoursExpanded, setHoursExpand
               {filesExpanded && placeFiles.length > 0 && (
                 <div style={{ padding: '0 12px 10px', display: 'flex', flexDirection: 'column', gap: 4 }}>
                   {placeFiles.map(f => (
-                    <button key={f.id} onClick={() => openFile(f.url).catch(() => {})} style={{ display: 'flex', alignItems: 'center', gap: 8, textDecoration: 'none', cursor: 'pointer', background: 'none', border: 'none', width: '100%', textAlign: 'left' }}>
+                    <button type="button" key={f.id} onClick={() => openFile(f.url).catch(() => {})} style={{ display: 'flex', alignItems: 'center', gap: 8, textDecoration: 'none', cursor: 'pointer', background: 'none', border: 'none', width: '100%', textAlign: 'left' }}>
                       {(f.mime_type || '').startsWith('image/') ? <FileImage size={12} color="#6b7280" /> : <File size={12} color="#6b7280" />}
                       <span className="text-content-secondary" style={{ fontSize: 'calc(12px * var(--fs-scale-body, 1))', flex: 1, overflow: 'hidden', textOverflow: 'ellipsis', whiteSpace: 'nowrap' }}>{f.original_name}</span>
                       {f.file_size && <span className="text-content-faint" style={{ fontSize: 'calc(11px * var(--fs-scale-caption, 1))', flexShrink: 0 }}>{formatFileSize(f.file_size)}</span>}
diff --git a/client/src/components/Planner/PlacesBulkCategoryModal.tsx b/client/src/components/Planner/PlacesBulkCategoryModal.tsx
index 56165234e..70d74a462 100644
--- a/client/src/components/Planner/PlacesBulkCategoryModal.tsx
+++ b/client/src/components/Planner/PlacesBulkCategoryModal.tsx
@@ -37,7 +37,7 @@ export function PlacesBulkCategoryModal({ count, categories, onPick, onClose }:
       }}>
         <div style={{ display: 'flex', alignItems: 'center', justifyContent: 'space-between', marginBottom: 4 }}>
           <span style={{ fontWeight: 600, fontSize: 14 }}>{t('places.changeCategory')}</span>
-          <button onClick={onClose} aria-label={t('common.close')} className="text-content-muted" style={{ background: 'none', border: 'none', cursor: 'pointer', padding: 4, display: 'flex' }}>
+          <button type="button" onClick={onClose} aria-label={t('common.close')} className="text-content-muted" style={{ background: 'none', border: 'none', cursor: 'pointer', padding: 4, display: 'flex' }}>
             <X size={15} strokeWidth={2} />
           </button>
         </div>
@@ -47,7 +47,7 @@ export function PlacesBulkCategoryModal({ count, categories, onPick, onClose }:
           {categories.map(c => {
             const CatIcon = getCategoryIcon(c.icon)
             return (
-              <button key={c.id} onClick={() => onPick(c.id)} className="text-content bg-transparent" style={rowStyle} onMouseEnter={hoverOn} onMouseLeave={hoverOff}>
+              <button type="button" key={c.id} onClick={() => onPick(c.id)} className="text-content bg-transparent" style={rowStyle} onMouseEnter={hoverOn} onMouseLeave={hoverOff}>
                 <CatIcon size={14} strokeWidth={2} color={c.color || 'var(--text-muted)'} />
                 <span style={{ flex: 1 }}>{c.name}</span>
               </button>
diff --git a/client/src/components/Planner/PlacesSidebarHeader.tsx b/client/src/components/Planner/PlacesSidebarHeader.tsx
index c8a52e48d..a760588dc 100644
--- a/client/src/components/Planner/PlacesSidebarHeader.tsx
+++ b/client/src/components/Planner/PlacesSidebarHeader.tsx
@@ -30,7 +30,7 @@ export function PlacesHeader(S: SidebarState) {
   } = S
   return (
     <div className="border-b border-edge-faint" style={{ padding: '14px 16px 10px', flexShrink: 0 }}>
-      {canEditPlaces && <button
+      {canEditPlaces && <button type="button"
         onClick={onAddPlace}
         className="bg-accent text-accent-text"
         style={{
@@ -44,7 +44,7 @@ export function PlacesHeader(S: SidebarState) {
       </button>}
       {canEditPlaces && <>
       <div style={{ display: 'flex', gap: 6, marginBottom: 10 }}>
-        <button
+        <button type="button"
           onClick={() => setFileImportOpen(true)}
           className="border border-dashed border-edge text-content-faint"
           style={{
@@ -56,7 +56,7 @@ export function PlacesHeader(S: SidebarState) {
         >
           <FileDown size={11} strokeWidth={2} /> {t('places.importFile')}
         </button>
-        <button
+        <button type="button"
           onClick={() => setListImportOpen(true)}
           className="border border-dashed border-edge text-content-faint"
           style={{
@@ -101,7 +101,7 @@ export function PlacesHeader(S: SidebarState) {
             {tabs.map(f => {
               const active = filter === f.id
               return (
-                <button
+                <button type="button"
                   key={f.id}
                   onClick={() => { setFilter(f.id); setSelectedIds(new Set()) }}
                   className={active ? 'bg-accent text-accent-text' : 'bg-surface-card text-content'}
@@ -145,7 +145,7 @@ export function PlacesHeader(S: SidebarState) {
           }}
         />
         {search && (
-          <button onClick={() => setSearch('')} style={{ position: 'absolute', right: 8, top: '50%', transform: 'translateY(-50%)', background: 'none', border: 'none', cursor: 'pointer', padding: 0, display: 'flex' }}>
+          <button type="button" onClick={() => setSearch('')} style={{ position: 'absolute', right: 8, top: '50%', transform: 'translateY(-50%)', background: 'none', border: 'none', cursor: 'pointer', padding: 0, display: 'flex' }}>
             <X size={12} strokeWidth={2} color="var(--text-faint)" />
           </button>
         )}
@@ -162,7 +162,7 @@ export function PlacesHeader(S: SidebarState) {
             : `${categoryFilters.size} ${t('places.categoriesSelected')}`
         return (
           <div style={{ marginTop: 6, position: 'relative', display: 'flex', gap: 6, alignItems: 'stretch' }}>
-            {categories.length > 0 && <button onClick={() => setCatDropOpen(v => !v)} className="bg-surface-card text-content" style={{
+            {categories.length > 0 && <button type="button" onClick={() => setCatDropOpen(v => !v)} className="bg-surface-card text-content" style={{
               flex: 1, minWidth: 0, display: 'flex', alignItems: 'center', justifyContent: 'space-between',
               padding: '6px 10px', borderRadius: 8, border: '1px solid var(--border-primary)',
               fontSize: 'calc(12px * var(--fs-scale-body, 1))',
@@ -173,7 +173,7 @@ export function PlacesHeader(S: SidebarState) {
             </button>}
             {/* Minimum-stars filter (#1435), same floors as the collections bar. */}
             <Tooltip label={t('places.filterByRating')} placement="bottom">
-              <button
+              <button type="button"
                 onClick={() => { setStarDropOpen(v => !v); setCatDropOpen(false) }}
                 aria-label={t('places.filterByRating')}
                 aria-expanded={starDropOpen}
@@ -203,7 +203,7 @@ export function PlacesHeader(S: SidebarState) {
                 {(['all', 5, 4, 3, 2, 1] as const).map(opt => {
                   const active = ratingFilter === opt
                   return (
-                    <button
+                    <button type="button"
                       key={String(opt)}
                       onClick={() => { setRatingFilter(opt as number | 'all'); setStarDropOpen(false) }}
                       className={`text-content ${active ? 'bg-surface-hover' : 'bg-transparent'}`}
@@ -230,7 +230,7 @@ export function PlacesHeader(S: SidebarState) {
             )}
             {canEditPlaces && (
               <Tooltip label={t('common.select')} placement="bottom">
-              <button
+              <button type="button"
                 onClick={() => { setSelectMode(v => !v); setSelectedIds(new Set()) }}
                 aria-label={t('common.select')}
                 aria-pressed={selectMode}
@@ -273,7 +273,7 @@ export function PlacesHeader(S: SidebarState) {
                   const active = categoryFilters.has(String(c.id))
                   const CatIcon = getCategoryIcon(c.icon)
                   return (
-                    <button key={c.id} onClick={() => toggleCategoryFilter(String(c.id))} className={`text-content ${active ? 'bg-surface-hover' : 'bg-transparent'}`} style={{
+                    <button type="button" key={c.id} onClick={() => toggleCategoryFilter(String(c.id))} className={`text-content ${active ? 'bg-surface-hover' : 'bg-transparent'}`} style={{
                       display: 'flex', alignItems: 'center', gap: 8, width: '100%',
                       padding: '6px 10px', borderRadius: 6, border: 'none', cursor: 'pointer',
                       fontFamily: 'inherit', fontSize: 'calc(12px * var(--fs-scale-body, 1))',
@@ -295,7 +295,7 @@ export function PlacesHeader(S: SidebarState) {
                 {places.some(p => p.category_id == null) && (() => {
                   const active = categoryFilters.has('uncategorized')
                   return (
-                    <button onClick={() => toggleCategoryFilter('uncategorized')} className={`text-content-muted ${active ? 'bg-surface-hover' : 'bg-transparent'}`} style={{
+                    <button type="button" onClick={() => toggleCategoryFilter('uncategorized')} className={`text-content-muted ${active ? 'bg-surface-hover' : 'bg-transparent'}`} style={{
                       display: 'flex', alignItems: 'center', gap: 8, width: '100%',
                       padding: '6px 10px', borderRadius: 6, border: 'none', cursor: 'pointer',
                       fontFamily: 'inherit', fontSize: 'calc(12px * var(--fs-scale-body, 1))',
@@ -314,7 +314,7 @@ export function PlacesHeader(S: SidebarState) {
                   )
                 })()}
                 {categoryFilters.size > 0 && (
-                  <button onClick={() => setCategoryFilters(new Set())} className="bg-transparent text-content-faint" style={{
+                  <button type="button" onClick={() => setCategoryFilters(new Set())} className="bg-transparent text-content-faint" style={{
                     display: 'flex', alignItems: 'center', justifyContent: 'center', gap: 4,
                     width: '100%', padding: '6px 10px', borderRadius: 6, border: 'none', cursor: 'pointer',
                     fontFamily: 'inherit', fontSize: 'calc(11px * var(--fs-scale-caption, 1))',
diff --git a/client/src/components/Planner/PlacesSidebarList.tsx b/client/src/components/Planner/PlacesSidebarList.tsx
index 9b2d75546..b5acc4d07 100644
--- a/client/src/components/Planner/PlacesSidebarList.tsx
+++ b/client/src/components/Planner/PlacesSidebarList.tsx
@@ -18,7 +18,7 @@ export function PlacesList(S: SidebarState) {
           <span className="text-content-faint" style={{ fontSize: 'calc(13px * var(--fs-scale-body, 1))' }}>
             {filter === 'unplanned' ? t('places.allPlanned') : t('places.noneFound')}
           </span>
-          {canEditPlaces && <button onClick={onAddPlace} className="text-content" style={{ fontSize: 'calc(12px * var(--fs-scale-body, 1))', background: 'none', border: 'none', cursor: 'pointer', textDecoration: 'underline', fontFamily: 'inherit' }}>
+          {canEditPlaces && <button type="button" onClick={onAddPlace} className="text-content" style={{ fontSize: 'calc(12px * var(--fs-scale-body, 1))', background: 'none', border: 'none', cursor: 'pointer', textDecoration: 'underline', fontFamily: 'inherit' }}>
             {t('places.addPlace')}
           </button>}
         </div>
diff --git a/client/src/components/Planner/PlacesSidebarListImportModal.tsx b/client/src/components/Planner/PlacesSidebarListImportModal.tsx
index dc0c613dd..9ab840e43 100644
--- a/client/src/components/Planner/PlacesSidebarListImportModal.tsx
+++ b/client/src/components/Planner/PlacesSidebarListImportModal.tsx
@@ -25,7 +25,7 @@ export function ListImportModal(S: SidebarState) {
         {hasMultipleListImportProviders && (
           <div style={{ display: 'flex', gap: 6, marginBottom: 10 }}>
             {availableListImportProviders.map(provider => (
-              <button
+              <button type="button"
                 key={provider}
                 onClick={() => setListImportProvider(provider)}
                 className={listImportProvider === provider ? 'bg-accent text-accent-text' : 'bg-surface-tertiary text-content-muted'}
@@ -67,7 +67,7 @@ export function ListImportModal(S: SidebarState) {
           </div>
         )}
         <div style={{ display: 'flex', gap: 8, marginTop: 16, justifyContent: 'flex-end' }}>
-          <button
+          <button type="button"
             onClick={() => { setListImportOpen(false); setListImportUrl('') }}
             className="text-content"
             style={{
@@ -78,7 +78,7 @@ export function ListImportModal(S: SidebarState) {
           >
             {t('common.cancel')}
           </button>
-          <button
+          <button type="button"
             onClick={handleListImport}
             disabled={!listImportUrl.trim() || listImportLoading}
             className={!listImportUrl.trim() || listImportLoading ? 'bg-surface-tertiary text-content-faint' : 'bg-accent text-accent-text'}
diff --git a/client/src/components/Planner/PlacesSidebarMobileDayPicker.tsx b/client/src/components/Planner/PlacesSidebarMobileDayPicker.tsx
index d26d478b2..6ac41c5a1 100644
--- a/client/src/components/Planner/PlacesSidebarMobileDayPicker.tsx
+++ b/client/src/components/Planner/PlacesSidebarMobileDayPicker.tsx
@@ -23,7 +23,7 @@ export function MobileDayPickerSheet(S: SidebarState) {
         </div>
         <div style={{ overflowY: 'auto', padding: '8px 12px' }}>
           {/* View details */}
-          <button
+          <button type="button"
             onClick={() => { onPlaceClick(dayPickerPlace.id); setDayPickerPlace(null); setMobileShowDays(false) }}
             className="bg-transparent text-content"
             style={{ display: 'flex', alignItems: 'center', gap: 12, width: '100%', padding: '12px 14px', borderRadius: 12, border: 'none', cursor: 'pointer', fontFamily: 'inherit', textAlign: 'left', fontSize: 'calc(14px * var(--fs-scale-body, 1))' }}
@@ -32,7 +32,7 @@ export function MobileDayPickerSheet(S: SidebarState) {
           </button>
           {/* Edit */}
           {canEditPlaces && (
-            <button
+            <button type="button"
               onClick={() => { onEditPlace(dayPickerPlace); setDayPickerPlace(null); setMobileShowDays(false) }}
               className="bg-transparent text-content"
               style={{ display: 'flex', alignItems: 'center', gap: 12, width: '100%', padding: '12px 14px', borderRadius: 12, border: 'none', cursor: 'pointer', fontFamily: 'inherit', textAlign: 'left', fontSize: 'calc(14px * var(--fs-scale-body, 1))' }}
@@ -43,7 +43,7 @@ export function MobileDayPickerSheet(S: SidebarState) {
           {/* Assign to day */}
           {days?.length > 0 && (
             <>
-              <button
+              <button type="button"
                 onClick={() => setMobileShowDays(v => !v)}
                 className="bg-transparent text-content"
               style={{ display: 'flex', alignItems: 'center', gap: 12, width: '100%', padding: '12px 14px', borderRadius: 12, border: 'none', cursor: 'pointer', fontFamily: 'inherit', textAlign: 'left', fontSize: 'calc(14px * var(--fs-scale-body, 1))' }}
@@ -54,7 +54,7 @@ export function MobileDayPickerSheet(S: SidebarState) {
               {mobileShowDays && (
                 <div style={{ paddingLeft: 20 }}>
                   {days.map((day, i) => (
-                    <button
+                    <button type="button"
                       key={day.id}
                       onClick={() => { onAssignToDay(dayPickerPlace.id, day.id); setDayPickerPlace(null); setMobileShowDays(false) }}
                       style={{ display: 'flex', alignItems: 'center', gap: 10, width: '100%', padding: '10px 14px', borderRadius: 10, border: 'none', cursor: 'pointer', background: 'transparent', fontFamily: 'inherit', textAlign: 'left' }}
@@ -73,7 +73,7 @@ export function MobileDayPickerSheet(S: SidebarState) {
           )}
           {/* Delete */}
           {canEditPlaces && (
-            <button
+            <button type="button"
               onClick={() => { onDeletePlace(dayPickerPlace.id); setDayPickerPlace(null); setMobileShowDays(false) }}
               style={{ display: 'flex', alignItems: 'center', gap: 12, width: '100%', padding: '12px 14px', borderRadius: 12, border: 'none', cursor: 'pointer', background: 'transparent', fontFamily: 'inherit', textAlign: 'left', fontSize: 'calc(14px * var(--fs-scale-body, 1))', color: '#ef4444' }}
             >
diff --git a/client/src/components/Planner/PlacesSidebarRow.tsx b/client/src/components/Planner/PlacesSidebarRow.tsx
index 332fd3a19..af17f3cfb 100644
--- a/client/src/components/Planner/PlacesSidebarRow.tsx
+++ b/client/src/components/Planner/PlacesSidebarRow.tsx
@@ -121,7 +121,7 @@ export const MemoPlaceRow = React.memo(function MemoPlaceRow({
       </div>
       <div style={{ flexShrink: 0, display: 'flex', alignItems: 'center' }}>
         {!selectMode && !inDay && selectedDayId && (
-          <button
+          <button type="button"
             onClick={e => { e.stopPropagation(); onAssignToDay(place.id) }}
             className="bg-surface-hover text-content-faint"
             style={{
diff --git a/client/src/components/Planner/PlacesSidebarSelectionBar.tsx b/client/src/components/Planner/PlacesSidebarSelectionBar.tsx
index 0c2adbf24..c94f34855 100644
--- a/client/src/components/Planner/PlacesSidebarSelectionBar.tsx
+++ b/client/src/components/Planner/PlacesSidebarSelectionBar.tsx
@@ -14,7 +14,7 @@ export function PlacesSelectionBar(S: SidebarState) {
         {t('places.selectionCount', { count: selectedIds.size })}
       </span>
       <Tooltip label={selectedIds.size === filtered.length && filtered.length > 0 ? t('common.deselectAll') : t('common.selectAll')} placement="bottom">
-      <button
+      <button type="button"
         onClick={() => {
           if (selectedIds.size === filtered.length) setSelectedIds(new Set())
           else setSelectedIds(new Set(filtered.map(p => p.id)))
@@ -33,7 +33,7 @@ export function PlacesSelectionBar(S: SidebarState) {
       </button>
       </Tooltip>
       <Tooltip label={t('places.changeCategory')} placement="bottom">
-      <button
+      <button type="button"
         onClick={() => { if (selectedIds.size === 0) return; setCategoryPickerOpen(true) }}
         disabled={selectedIds.size === 0}
         aria-label={t('places.changeCategory')}
@@ -51,7 +51,7 @@ export function PlacesSelectionBar(S: SidebarState) {
       </Tooltip>
       {collectionsEnabled && (
         <Tooltip label={t('inspector.saveToCollection')} placement="bottom">
-        <button
+        <button type="button"
           onClick={() => { if (selectedIds.size === 0) return; setSaveToListOpen(true) }}
           disabled={selectedIds.size === 0}
           aria-label={t('inspector.saveToCollection')}
@@ -70,7 +70,7 @@ export function PlacesSelectionBar(S: SidebarState) {
       )}
       {collectionsEnabled && (
         <Tooltip label={t('collections.markVisitedSelection')} placement="bottom">
-        <button
+        <button type="button"
           onClick={() => { if (selectedIds.size === 0) return; void markSelectionVisited() }}
           disabled={selectedIds.size === 0 || markVisitedBusy}
           aria-label={t('collections.markVisitedSelection')}
@@ -88,7 +88,7 @@ export function PlacesSelectionBar(S: SidebarState) {
         </Tooltip>
       )}
       <Tooltip label={t('places.deleteSelected')} placement="bottom">
-      <button
+      <button type="button"
         onClick={() => {
           if (selectedIds.size === 0) return
           if (isMobile) setPendingDeleteIds(Array.from(selectedIds))
diff --git a/client/src/components/Planner/ReservationsPanel.tsx b/client/src/components/Planner/ReservationsPanel.tsx
index 74d5eb2a6..c69d0b79d 100644
--- a/client/src/components/Planner/ReservationsPanel.tsx
+++ b/client/src/components/Planner/ReservationsPanel.tsx
@@ -229,7 +229,7 @@ function ReservationCard({ r, tripId, onEdit, onDelete, files = [], onNavigateTo
             maxWidth: 140, whiteSpace: 'nowrap', overflow: 'hidden', textOverflow: 'ellipsis',
           }}>{r.title}</span>
           {canEdit && (
-            <button onClick={() => onEdit(r)} title={t('common.edit')} className="bg-transparent text-content-faint" style={{
+            <button type="button" onClick={() => onEdit(r)} title={t('common.edit')} className="bg-transparent text-content-faint" style={{
               appearance: 'none', border: 'none',
               width: 26, height: 26, borderRadius: 6, display: 'grid', placeItems: 'center',
               cursor: 'pointer', flexShrink: 0,
@@ -240,7 +240,7 @@ function ReservationCard({ r, tripId, onEdit, onDelete, files = [], onNavigateTo
             </button>
           )}
           {canEdit && (
-            <button onClick={() => setShowDeleteConfirm(true)} title={t('common.delete')} className="bg-transparent text-content-faint" style={{
+            <button type="button" onClick={() => setShowDeleteConfirm(true)} title={t('common.delete')} className="bg-transparent text-content-faint" style={{
               appearance: 'none', border: 'none',
               width: 26, height: 26, borderRadius: 6, display: 'grid', placeItems: 'center',
               cursor: 'pointer', flexShrink: 0,
@@ -522,11 +522,11 @@ function ReservationCard({ r, tripId, onEdit, onDelete, files = [], onNavigateTo
               {t('reservations.confirm.deleteBody', { name: r.title })}
             </div>
             <div style={{ display: 'flex', gap: 8, justifyContent: 'flex-end', marginTop: 4 }}>
-              <button onClick={() => setShowDeleteConfirm(false)} className="text-content-muted" style={{
+              <button type="button" onClick={() => setShowDeleteConfirm(false)} className="text-content-muted" style={{
                 fontSize: 'calc(12px * var(--fs-scale-body, 1))', background: 'none', border: '1px solid var(--border-primary)',
                 borderRadius: 8, padding: '6px 14px', cursor: 'pointer', fontFamily: 'inherit',
               }}>{t('common.cancel')}</button>
-              <button onClick={handleDelete} className="bg-[#ef4444] text-white" style={{
+              <button type="button" onClick={handleDelete} className="bg-[#ef4444] text-white" style={{
                 fontSize: 'calc(12px * var(--fs-scale-body, 1))',
                 border: 'none', borderRadius: 8, padding: '6px 16px', cursor: 'pointer', fontWeight: 600, fontFamily: 'inherit',
               }}>{t('common.confirm')}</button>
@@ -561,7 +561,7 @@ function Section({ title, count, children, defaultOpen = true, accent, storageKe
   }, [open, storageKey])
   return (
     <div style={{ marginBottom: 28 }}>
-      <button onClick={() => setOpen(o => !o)} style={{
+      <button type="button" onClick={() => setOpen(o => !o)} style={{
         display: 'flex', alignItems: 'center', gap: 8, width: '100%',
         background: 'none', border: 'none', cursor: 'pointer', padding: '4px 0', marginBottom: 12, fontFamily: 'inherit',
         userSelect: 'none',
@@ -632,7 +632,7 @@ function TransitJourneyCard({ r, days, onOpen, onDelete, canEdit, tripId, contri
           </div>
         </div>
         {canEdit && (
-          <button
+          <button type="button"
             onClick={e => { e.stopPropagation(); setConfirmOpen(true) }}
             title={t('common.delete')}
             className="bg-transparent text-content-faint"
@@ -680,8 +680,8 @@ function TransitJourneyCard({ r, days, onOpen, onDelete, canEdit, tripId, contri
             <div className="text-content" style={{ fontWeight: 600, fontSize: 'calc(14px * var(--fs-scale-body, 1))', marginBottom: 6 }}>{t('reservations.confirm.deleteTitle')}</div>
             <div className="text-content-muted" style={{ fontSize: 'calc(12.5px * var(--fs-scale-body, 1))', marginBottom: 14 }}>{t('reservations.confirm.deleteBody', { name: r.title })}</div>
             <div style={{ display: 'flex', justifyContent: 'flex-end', gap: 8 }}>
-              <button onClick={e => { e.stopPropagation(); setConfirmOpen(false) }} className="text-content-muted" style={{ padding: '7px 14px', borderRadius: 9, border: '1px solid var(--border-primary)', background: 'none', fontSize: 'calc(12px * var(--fs-scale-body, 1))', cursor: 'pointer', fontFamily: 'inherit' }}>{t('common.cancel')}</button>
-              <button onClick={e => { e.stopPropagation(); setConfirmOpen(false); onDelete(r.id) }} style={{ padding: '7px 14px', borderRadius: 9, border: 'none', background: '#ef4444', color: '#fff', fontSize: 'calc(12px * var(--fs-scale-body, 1))', fontWeight: 600, cursor: 'pointer', fontFamily: 'inherit' }}>{t('common.delete')}</button>
+              <button type="button" onClick={e => { e.stopPropagation(); setConfirmOpen(false) }} className="text-content-muted" style={{ padding: '7px 14px', borderRadius: 9, border: '1px solid var(--border-primary)', background: 'none', fontSize: 'calc(12px * var(--fs-scale-body, 1))', cursor: 'pointer', fontFamily: 'inherit' }}>{t('common.cancel')}</button>
+              <button type="button" onClick={e => { e.stopPropagation(); setConfirmOpen(false); onDelete(r.id) }} style={{ padding: '7px 14px', borderRadius: 9, border: 'none', background: '#ef4444', color: '#fff', fontSize: 'calc(12px * var(--fs-scale-body, 1))', fontWeight: 600, cursor: 'pointer', fontFamily: 'inherit' }}>{t('common.delete')}</button>
             </div>
           </div>
         </div>,
@@ -837,7 +837,7 @@ export default function ReservationsPanel({ tripId, reservations, days, assignme
             <>
               <div className="hidden md:block" style={{ width: 1, height: 22, background: 'var(--border-faint)', flexShrink: 0 }} />
               <div className="hidden md:inline-flex" style={{ gap: 4, flexWrap: 'wrap', flex: 1, minWidth: 0 }}>
-                <button
+                <button type="button"
                   onClick={() => { setTypeFilters(new Set()); sessionStorage.removeItem(storageKey) }}
                   className={typeFilters.size === 0 ? 'bg-surface-card text-content' : 'bg-transparent text-content-muted'}
                   style={{
@@ -859,7 +859,7 @@ export default function ReservationsPanel({ tripId, reservations, days, assignme
                   const active = typeFilters.has(opt.value)
                   const Icon = opt.Icon
                   return (
-                    <button
+                    <button type="button"
                       key={opt.value}
                       onClick={() => toggleTypeFilter(opt.value)}
                       className={active ? 'bg-surface-card text-content' : 'bg-transparent text-content-muted'}
@@ -896,7 +896,7 @@ export default function ReservationsPanel({ tripId, reservations, days, assignme
           {canEdit && (
             <div style={{ display: 'flex', gap: 6, marginLeft: 'auto', flexShrink: 0 }}>
               {onImport && bookingImportAvailable && (
-                <button onClick={onImport} className="bg-surface-card text-content" style={{
+                <button type="button" onClick={onImport} className="bg-surface-card text-content" style={{
                   appearance: 'none', border: '1px solid var(--border-primary)', cursor: 'pointer', fontFamily: 'inherit',
                   display: 'inline-flex', alignItems: 'center', gap: 6,
                   padding: '8px 13px', borderRadius: 10, fontSize: 'calc(13px * var(--fs-scale-body, 1))', fontWeight: 500,
@@ -911,7 +911,7 @@ export default function ReservationsPanel({ tripId, reservations, days, assignme
                 </button>
               )}
               {onAirTrailImport && airTrailAvailable && (
-                <button onClick={onAirTrailImport} className="bg-surface-secondary text-content" style={{
+                <button type="button" onClick={onAirTrailImport} className="bg-surface-secondary text-content" style={{
                   appearance: 'none', border: '1px solid var(--border-primary)', cursor: 'pointer', fontFamily: 'inherit',
                   display: 'inline-flex', alignItems: 'center', gap: 6,
                   padding: '8px 14px', borderRadius: 10, fontSize: 'calc(13px * var(--fs-scale-body, 1))', fontWeight: 500, boxSizing: 'border-box',
@@ -925,7 +925,7 @@ export default function ReservationsPanel({ tripId, reservations, days, assignme
                   <span className="hidden sm:inline">{t('reservations.airtrail.cta')}</span>
                 </button>
               )}
-              <button onClick={onAdd} className="bg-accent text-accent-text" style={{
+              <button type="button" onClick={onAdd} className="bg-accent text-accent-text" style={{
                 appearance: 'none', border: 'none', cursor: 'pointer', fontFamily: 'inherit',
                 display: 'inline-flex', alignItems: 'center', gap: 6,
                 padding: '9px 14px', borderRadius: 10, fontSize: 'calc(13px * var(--fs-scale-body, 1))', fontWeight: 500,
@@ -952,7 +952,7 @@ export default function ReservationsPanel({ tripId, reservations, days, assignme
             // page, so the import in particular went unnoticed (#2007).
             action={canEdit ? (
               <div style={{ display: 'flex', gap: 8, flexWrap: 'wrap', justifyContent: 'center' }}>
-                <button onClick={onAdd} className="bg-accent text-accent-text" style={CTA_STYLE}>
+                <button type="button" onClick={onAdd} className="bg-accent text-accent-text" style={CTA_STYLE}>
                   <Plus size={14} strokeWidth={2} />
                   {t(addManualKey)}
                 </button>
diff --git a/client/src/components/Planner/SubscribeLinks.tsx b/client/src/components/Planner/SubscribeLinks.tsx
index e5eed99ab..38ae62c3d 100644
--- a/client/src/components/Planner/SubscribeLinks.tsx
+++ b/client/src/components/Planner/SubscribeLinks.tsx
@@ -114,7 +114,7 @@ function UrlRow({ label, hint, url, copied, onCopy }: {
         }}>
           {url}
         </div>
-        <button
+        <button type="button"
           onClick={onCopy}
           title="Copy"
           style={{
diff --git a/client/src/components/Planner/TransitJourneyModal.tsx b/client/src/components/Planner/TransitJourneyModal.tsx
index 2ea5d4fcf..37cda8949 100644
--- a/client/src/components/Planner/TransitJourneyModal.tsx
+++ b/client/src/components/Planner/TransitJourneyModal.tsx
@@ -142,7 +142,7 @@ export default function TransitJourneyModal({ reservation, onClose, onSave, onDe
       footer={
         <div style={{ display: 'flex', alignItems: 'center', gap: 8, flexWrap: 'wrap' }}>
           {canEdit && (
-            <button onClick={() => setConfirmDelete(true)} aria-label={t('common.delete')} title={t('common.delete')} style={{
+            <button type="button" onClick={() => setConfirmDelete(true)} aria-label={t('common.delete')} title={t('common.delete')} style={{
               display: 'inline-flex', alignItems: 'center', gap: 5, padding: isMobile ? '9px 11px' : '8px 14px', borderRadius: 10,
               border: '1px solid rgba(239,68,68,0.3)', background: 'rgba(239,68,68,0.06)', color: '#ef4444',
               fontSize: 'calc(12px * var(--fs-scale-body, 1))', fontWeight: 500, cursor: 'pointer', fontFamily: 'inherit',
@@ -152,7 +152,7 @@ export default function TransitJourneyModal({ reservation, onClose, onSave, onDe
           )}
           <div style={{ flex: 1 }} />
           {canEdit && (
-            <button onClick={onChangeRoute} className="text-content-muted" style={{
+            <button type="button" onClick={onChangeRoute} className="text-content-muted" style={{
               display: 'inline-flex', alignItems: 'center', gap: 6, padding: '8px 16px', borderRadius: 10,
               border: '1px solid var(--border-primary)', background: 'none',
               fontSize: 'calc(12px * var(--fs-scale-body, 1))', cursor: 'pointer', fontFamily: 'inherit',
@@ -161,7 +161,7 @@ export default function TransitJourneyModal({ reservation, onClose, onSave, onDe
             </button>
           )}
           {canEdit ? (
-            <button onClick={save} disabled={saving || !title.trim() || !dirty} className="bg-[var(--text-primary)] text-[var(--bg-primary)]" style={{
+            <button type="button" onClick={save} disabled={saving || !title.trim() || !dirty} className="bg-[var(--text-primary)] text-[var(--bg-primary)]" style={{
               padding: '8px 20px', borderRadius: 10, border: 'none',
               fontSize: 'calc(12px * var(--fs-scale-body, 1))', fontWeight: 600, cursor: 'pointer', fontFamily: 'inherit',
               opacity: saving || !title.trim() || !dirty ? 0.5 : 1,
@@ -169,7 +169,7 @@ export default function TransitJourneyModal({ reservation, onClose, onSave, onDe
               {saving ? t('common.saving') : t('common.save')}
             </button>
           ) : (
-            <button onClick={onClose} className="bg-accent text-accent-text" style={{ padding: '8px 20px', borderRadius: 10, border: 'none', fontSize: 'calc(12px * var(--fs-scale-body, 1))', fontWeight: 600, cursor: 'pointer', fontFamily: 'inherit' }}>
+            <button type="button" onClick={onClose} className="bg-accent text-accent-text" style={{ padding: '8px 20px', borderRadius: 10, border: 'none', fontSize: 'calc(12px * var(--fs-scale-body, 1))', fontWeight: 600, cursor: 'pointer', fontFamily: 'inherit' }}>
               {t('common.close')}
             </button>
           )}
@@ -198,7 +198,7 @@ export default function TransitJourneyModal({ reservation, onClose, onSave, onDe
               <div className="text-content" style={{ display: 'flex', alignItems: 'center', gap: 7, fontSize: 'calc(17px * var(--fs-scale-subtitle, 1))', fontWeight: 700, letterSpacing: '-0.015em', minWidth: 0 }}>
                 <span style={{ minWidth: 0, overflow: 'hidden' }}><TransitTitle title={title} iconSize={15} /></span>
                 {canEdit && (
-                  <button onClick={() => setEditingTitle(true)} aria-label={t('common.edit')} title={t('common.edit')} className="text-content-faint" style={{ border: 'none', background: 'none', padding: 3, cursor: 'pointer', display: 'flex', flexShrink: 0 }}>
+                  <button type="button" onClick={() => setEditingTitle(true)} aria-label={t('common.edit')} title={t('common.edit')} className="text-content-faint" style={{ border: 'none', background: 'none', padding: 3, cursor: 'pointer', display: 'flex', flexShrink: 0 }}>
                     <Pencil size={13} strokeWidth={1.8} />
                   </button>
                 )}
diff --git a/client/src/components/Planner/TransitSearchPanel.tsx b/client/src/components/Planner/TransitSearchPanel.tsx
index dd8478b67..100fc4151 100644
--- a/client/src/components/Planner/TransitSearchPanel.tsx
+++ b/client/src/components/Planner/TransitSearchPanel.tsx
@@ -149,7 +149,7 @@ function StopPicker({ label, value, onPick, quickPicks, near, placeholder }: {
         <div className="bg-surface-card border border-edge" style={{ position: 'absolute', top: '100%', left: 0, right: 0, marginTop: 4, borderRadius: 10, boxShadow: '0 8px 32px rgba(0,0,0,0.14)', zIndex: 30, overflow: 'hidden', maxHeight: 240, overflowY: 'auto' }}>
           {results.length > 0
             ? results.map((r, i) => (
-              <button key={i} onClick={() => { onPick({ name: r.name, lat: r.lat, lng: r.lng }); setText(''); setResults([]); setOpen(false) }}
+              <button type="button" key={i} onClick={() => { onPick({ name: r.name, lat: r.lat, lng: r.lng }); setText(''); setResults([]); setOpen(false) }}
                 className="text-content"
                 style={{ display: 'flex', alignItems: 'center', gap: 8, width: '100%', textAlign: 'left', padding: '8px 10px', border: 'none', background: 'none', cursor: 'pointer', fontFamily: 'inherit', fontSize: 'calc(13px * var(--fs-scale-body, 1))' }}
                 onMouseEnter={e => e.currentTarget.style.background = 'var(--bg-hover)'}
@@ -162,7 +162,7 @@ function StopPicker({ label, value, onPick, quickPicks, near, placeholder }: {
               </button>
             ))
             : quickPicks.map((p, i) => (
-              <button key={i} onClick={() => { onPick(p); setText(''); setOpen(false) }}
+              <button type="button" key={i} onClick={() => { onPick(p); setText(''); setOpen(false) }}
                 className="text-content"
                 style={{ display: 'flex', alignItems: 'center', gap: 8, width: '100%', textAlign: 'left', padding: '8px 10px', border: 'none', background: 'none', cursor: 'pointer', fontFamily: 'inherit', fontSize: 'calc(13px * var(--fs-scale-body, 1))' }}
                 onMouseEnter={e => e.currentTarget.style.background = 'var(--bg-hover)'}
@@ -206,7 +206,7 @@ function ItineraryCard({ it, tzFrom, tzTo, is12h, expanded, onToggle, onAdd, add
   const walkMins = Math.round(it.walkSeconds / 60)
   return (
     <div className="bg-surface-card border border-edge" style={{ borderRadius: 14, overflow: 'hidden' }}>
-      <button onClick={onToggle} style={{ display: 'block', width: '100%', textAlign: 'left', padding: '12px 14px', border: 'none', background: 'none', cursor: 'pointer', fontFamily: 'inherit' }}>
+      <button type="button" onClick={onToggle} style={{ display: 'block', width: '100%', textAlign: 'left', padding: '12px 14px', border: 'none', background: 'none', cursor: 'pointer', fontFamily: 'inherit' }}>
         <div style={{ display: 'flex', alignItems: 'baseline', gap: 10, flexWrap: 'wrap' }}>
           <span className="text-content" style={{ fontSize: 'calc(15px * var(--fs-scale-subtitle, 1))', fontWeight: 700, letterSpacing: '-0.01em' }}>
             {fmtTimeInTz(it.startTime, tzFrom, is12h)} – {fmtTimeInTz(it.endTime, tzTo, is12h)}
@@ -289,7 +289,7 @@ function ItineraryCard({ it, tzFrom, tzTo, is12h, expanded, onToggle, onAdd, add
               {[...new Set(transitLegs.map(l => l.agency).filter(Boolean))].join(' · ')}
             </div>
           )}
-          <button
+          <button type="button"
             onClick={onAdd}
             disabled={adding}
             className="bg-accent text-accent-text"
@@ -507,7 +507,7 @@ export default function TransitSearchPanel({ day, days, places, accommodations =
         <div style={{ display: 'flex', flexDirection: isMobile ? 'column' : 'row', gap: 8, alignItems: isMobile ? 'stretch' : 'flex-end' }}>
           <StopPicker label={t('transit.from')} value={from} onPick={setFrom} quickPicks={quickPicks} near={near} placeholder={t('transit.searchStop')} />
           {!isMobile && (
-            <button
+            <button type="button"
               onClick={() => { const f = from; setFrom(to); setTo(f) }}
               aria-label={t('transit.swap')}
               title={t('transit.swap')}
@@ -525,8 +525,8 @@ export default function TransitSearchPanel({ day, days, places, accommodations =
           <div style={{ display: 'flex', alignItems: 'center', justifyContent: 'space-between', gap: 10, flexWrap: 'wrap' }}>
             <div style={{ display: 'flex', alignItems: 'center', gap: 8, flexWrap: 'wrap' }}>
               <div className="bg-surface-secondary" style={{ display: 'flex', borderRadius: 9, padding: 3 }}>
-                <button onClick={() => setArriveBy(false)} style={segBtn(!arriveBy)}>{t('transit.depart')}</button>
-                <button onClick={() => setArriveBy(true)} style={segBtn(arriveBy)}>{t('transit.arrive')}</button>
+                <button type="button" onClick={() => setArriveBy(false)} style={segBtn(!arriveBy)}>{t('transit.depart')}</button>
+                <button type="button" onClick={() => setArriveBy(true)} style={segBtn(arriveBy)}>{t('transit.arrive')}</button>
               </div>
               <div style={{ width: 110 }}>
                 <CustomTimePicker value={time} onChange={setTime} />
@@ -552,7 +552,7 @@ export default function TransitSearchPanel({ day, days, places, accommodations =
               {MODE_GROUPS.map(m => {
                 const active = activeModes.has(m.key)
                 return (
-                  <button key={m.key} onClick={() => toggleMode(m.key)}
+                  <button type="button" key={m.key} onClick={() => toggleMode(m.key)}
                     className={active ? 'bg-surface-card text-content' : 'text-content-faint'}
                     style={{
                       display: 'inline-flex', alignItems: 'center', gap: 5, padding: '5px 11px', borderRadius: 99,
@@ -569,7 +569,7 @@ export default function TransitSearchPanel({ day, days, places, accommodations =
                 )
               })}
             </div>
-            <button
+            <button type="button"
               onClick={search}
               disabled={!from || !to || loading}
               className="bg-accent text-accent-text"
diff --git a/client/src/components/Planner/placeHoursFormat.ts b/client/src/components/Planner/placeHoursFormat.ts
index 4413b0a01..e80d1a9db 100644
--- a/client/src/components/Planner/placeHoursFormat.ts
+++ b/client/src/components/Planner/placeHoursFormat.ts
@@ -17,7 +17,7 @@ export function convertHoursLine(line: string, timeFormat: string): string {
   if (timeFormat === '12h' && !hasAmPm) {
     // 24h → 12h: "10:00" → "10:00 AM", "21:00" → "9:00 PM", "Uhr" entfernen
     return line.replace(/\s*Uhr/g, '').replace(/(\d{1,2}):(\d{2})/g, (match, h, m) => {
-      const hour = parseInt(h)
+      const hour = Number.parseInt(h)
       if (isNaN(hour)) return match
       const period = hour >= 12 ? 'PM' : 'AM'
       const h12 = hour === 0 ? 12 : hour > 12 ? hour - 12 : hour
@@ -27,7 +27,7 @@ export function convertHoursLine(line: string, timeFormat: string): string {
   if (timeFormat !== '12h' && hasAmPm) {
     // 12h → 24h: "10:00 AM" → "10:00", "9:00 PM" → "21:00"
     return line.replace(/(\d{1,2}):(\d{2})\s*(AM|PM)/gi, (_, h, m, p) => {
-      let hour = parseInt(h)
+      let hour = Number.parseInt(h)
       if (p.toUpperCase() === 'PM' && hour !== 12) hour += 12
       if (p.toUpperCase() === 'AM' && hour === 12) hour = 0
       return `${String(hour).padStart(2, '0')}:${m}`
diff --git a/client/src/components/Planner/placeOpenState.ts b/client/src/components/Planner/placeOpenState.ts
index 14ce51c76..764f624de 100644
--- a/client/src/components/Planner/placeOpenState.ts
+++ b/client/src/components/Planner/placeOpenState.ts
@@ -67,8 +67,8 @@ function localParts(now: Date, timeZone: string | null): { day: number; minutes:
     }).formatToParts(now)
     const value = (type: Intl.DateTimeFormatPartTypes) => parts.find(p => p.type === type)?.value ?? ''
     const day = WEEKDAY_NUMBER[value('weekday')]
-    const hour = parseInt(value('hour'), 10)
-    const minute = parseInt(value('minute'), 10)
+    const hour = Number.parseInt(value('hour'), 10)
+    const minute = Number.parseInt(value('minute'), 10)
     if (day === undefined || Number.isNaN(hour) || Number.isNaN(minute)) return null
     return {
       day,
diff --git a/client/src/components/Plugins/PluginContributions.tsx b/client/src/components/Plugins/PluginContributions.tsx
index 6972e1697..a1aafc283 100644
--- a/client/src/components/Plugins/PluginContributions.tsx
+++ b/client/src/components/Plugins/PluginContributions.tsx
@@ -98,7 +98,7 @@ export function PluginActions({ items, tripId, className }: { items: ViewContrib
   return (
     <>
       {actions.map((a) => (
-        <button
+        <button type="button"
           key={a.pluginId + a.id}
           onClick={(e) => run(a, e)}
           title={a.label}
@@ -112,7 +112,7 @@ export function PluginActions({ items, tripId, className }: { items: ViewContrib
           <div className="bg-surface-card rounded-xl shadow-xl w-full max-w-lg h-[70vh] flex flex-col overflow-hidden" onClick={(e) => e.stopPropagation()}>
             <div className="flex items-center justify-between px-4 py-2.5 border-b border-edge shrink-0">
               <span className="text-sm font-medium text-content truncate">{frame.label}</span>
-              <button onClick={() => setFrame(null)} className="text-content-muted hover:text-content"><X size={16} /></button>
+              <button type="button" onClick={() => setFrame(null)} className="text-content-muted hover:text-content"><X size={16} /></button>
             </div>
             <div className="flex-1 min-h-0">
               <PluginFrame pluginId={frame.pluginId} tripId={tripId != null ? String(tripId) : null} title={frame.label} fill surface="action-frame" />
diff --git a/client/src/components/Settings/AccountTab.tsx b/client/src/components/Settings/AccountTab.tsx
index e9a2488b6..84798bbb9 100644
--- a/client/src/components/Settings/AccountTab.tsx
+++ b/client/src/components/Settings/AccountTab.tsx
@@ -198,7 +198,7 @@ export default function AccountTab(): React.ReactElement {
                 placeholder={t('settings.confirmPassword')}
                 className="w-full px-3 py-2 border border-slate-300 rounded-lg text-sm focus:ring-2 focus:ring-slate-400 focus:border-transparent"
               />
-              <button
+              <button type="button"
                 onClick={async () => {
                   if (!currentPassword) return toast.error(t('settings.currentPasswordRequired'))
                   if (!newPassword) return toast.error(t('settings.passwordRequired'))
@@ -415,7 +415,7 @@ export default function AccountTab(): React.ReactElement {
               </div>
             )}
             <input ref={avatarInputRef} type="file" accept="image/*" onChange={handleAvatarUpload} style={{ display: 'none' }} />
-            <button
+            <button type="button"
               onClick={() => avatarInputRef.current?.click()}
               style={{
                 position: 'absolute', bottom: -3, right: -3,
@@ -431,7 +431,7 @@ export default function AccountTab(): React.ReactElement {
               <Camera size={14} />
             </button>
             {user?.avatar_url && (
-              <button
+              <button type="button"
                 onClick={handleAvatarRemove}
                 className="bg-[#ef4444] text-white"
                 style={{
@@ -470,7 +470,7 @@ export default function AccountTab(): React.ReactElement {
         </div>
 
         <div style={{ display: 'flex', justifyContent: 'space-between', alignItems: 'center', marginTop: 12 }}>
-          <button
+          <button type="button"
             onClick={saveProfile}
             disabled={saving}
             className="flex items-center gap-2 px-4 py-2 bg-slate-900 text-white rounded-lg text-sm hover:bg-slate-700 disabled:bg-slate-400"
@@ -479,7 +479,7 @@ export default function AccountTab(): React.ReactElement {
             <span className="hidden sm:inline">{t('settings.saveProfile')}</span>
             <span className="sm:hidden">{t('common.save')}</span>
           </button>
-          <button
+          <button type="button"
             onClick={async () => {
               if (user?.role === 'admin') {
                 try {
@@ -523,7 +523,7 @@ export default function AccountTab(): React.ReactElement {
               {t('settings.deleteBlockedMessage')}
             </p>
             <div style={{ display: 'flex', justifyContent: 'flex-end' }}>
-              <button
+              <button type="button"
                 onClick={() => setShowDeleteConfirm(false)}
                 className="border border-edge bg-surface-card text-content-secondary"
                 style={{
@@ -559,7 +559,7 @@ export default function AccountTab(): React.ReactElement {
               {t('settings.deleteAccountWarning')}
             </p>
             <div style={{ display: 'flex', justifyContent: 'flex-end', gap: 8 }}>
-              <button
+              <button type="button"
                 onClick={() => setShowDeleteConfirm(false)}
                 className="border border-edge bg-surface-card text-content-secondary"
                 style={{
@@ -569,7 +569,7 @@ export default function AccountTab(): React.ReactElement {
               >
                 {t('common.cancel')}
               </button>
-              <button
+              <button type="button"
                 onClick={async () => {
                   try {
                     await authApi.deleteOwnAccount()
diff --git a/client/src/components/Settings/AirTrailConnectionSection.tsx b/client/src/components/Settings/AirTrailConnectionSection.tsx
index d41d46948..1482217c7 100644
--- a/client/src/components/Settings/AirTrailConnectionSection.tsx
+++ b/client/src/components/Settings/AirTrailConnectionSection.tsx
@@ -118,14 +118,14 @@ export default function AirTrailConnectionSection(): React.ReactElement {
         </div>
 
         <div className="flex flex-wrap items-center gap-3">
-          <button
+          <button type="button"
             onClick={handleSave}
             disabled={saving || loading || !canSave}
             className="flex items-center gap-2 px-4 py-2 bg-slate-900 text-white rounded-lg text-sm hover:bg-slate-700 disabled:bg-slate-400"
           >
             <Save className="w-4 h-4" /> {t('common.save')}
           </button>
-          <button
+          <button type="button"
             onClick={handleTest}
             disabled={testing || loading || !url.trim()}
             className="flex items-center gap-2 px-4 py-2 border border-slate-200 rounded-lg text-sm hover:bg-slate-50"
diff --git a/client/src/components/Settings/AppearanceSettingsTab.tsx b/client/src/components/Settings/AppearanceSettingsTab.tsx
index 46893a1e8..95e404aa0 100644
--- a/client/src/components/Settings/AppearanceSettingsTab.tsx
+++ b/client/src/components/Settings/AppearanceSettingsTab.tsx
@@ -22,9 +22,9 @@ function channelLum(v: number): number {
 function relLuminance(hex: string): number {
   const c = hex.replace('#', '')
   const full = c.length === 3 ? c.split('').map((x) => x + x).join('') : c
-  const r = channelLum(parseInt(full.slice(0, 2), 16) / 255)
-  const g = channelLum(parseInt(full.slice(2, 4), 16) / 255)
-  const b = channelLum(parseInt(full.slice(4, 6), 16) / 255)
+  const r = channelLum(Number.parseInt(full.slice(0, 2), 16) / 255)
+  const g = channelLum(Number.parseInt(full.slice(2, 4), 16) / 255)
+  const b = channelLum(Number.parseInt(full.slice(4, 6), 16) / 255)
   return 0.2126 * r + 0.7152 * g + 0.0722 * b
 }
 function contrastRatio(a: string, b: string): number {
@@ -162,7 +162,7 @@ export default function AppearanceSettingsTab(): React.ReactElement {
                 (opt.value === 'light' && cur === false) ||
                 (opt.value === 'dark' && cur === true)
               return (
-                <button key={opt.value} onClick={() => setMode(opt.value)} style={segStyle(active)}>
+                <button type="button" key={opt.value} onClick={() => setMode(opt.value)} style={segStyle(active)}>
                   <span className="hidden sm:inline-flex"><opt.icon size={16} /></span>
                   {opt.value === 'auto' ? (
                     <>
@@ -186,7 +186,7 @@ export default function AppearanceSettingsTab(): React.ReactElement {
               const active = cfg.schemeId === s.id
               const dot = isDark ? s.swatch.dark : s.swatch.light
               return (
-                <button
+                <button type="button"
                   key={s.id}
                   onClick={() => update({ schemeId: s.id })}
                   style={{
@@ -205,7 +205,7 @@ export default function AppearanceSettingsTab(): React.ReactElement {
               )
             })}
             {/* Custom */}
-            <button
+            <button type="button"
               onClick={() => update({ schemeId: 'custom', accent: cfg.accent ?? { light: accentLight, dark: accentDark } })}
               style={{
                 display: 'flex', alignItems: 'center', gap: 8, padding: '10px 12px', borderRadius: 10,
@@ -229,7 +229,7 @@ export default function AppearanceSettingsTab(): React.ReactElement {
             </label>
             <div className="flex flex-wrap gap-2 mb-3">
               {CUSTOM_ACCENT_PRESETS.map((c) => (
-                <button
+                <button type="button"
                   key={c}
                   aria-label={c}
                   onClick={() => update({ accent: { light: c, dark: c } })}
@@ -296,7 +296,7 @@ export default function AppearanceSettingsTab(): React.ReactElement {
               { value: 'comfortable', label: tr('settings.appearance.comfortable', 'Comfortable') },
               { value: 'compact', label: tr('settings.appearance.compact', 'Compact') },
             ].map((opt) => (
-              <button key={opt.value} onClick={() => update({ density: opt.value as AppearanceConfig['density'] })} style={segStyle(cfg.density === opt.value)}>
+              <button type="button" key={opt.value} onClick={() => update({ density: opt.value as AppearanceConfig['density'] })} style={segStyle(cfg.density === opt.value)}>
                 {opt.label}
               </button>
             ))}
@@ -413,7 +413,7 @@ export default function AppearanceSettingsTab(): React.ReactElement {
       </Section>
 
       <div className="flex justify-end mb-6">
-        <button
+        <button type="button"
           onClick={resetAll}
           className="flex items-center gap-2 text-sm font-medium text-content-muted hover:text-content"
           style={{ background: 'none', border: 'none', cursor: 'pointer', padding: '6px 4px' }}
diff --git a/client/src/components/Settings/DisplaySettingsTab.tsx b/client/src/components/Settings/DisplaySettingsTab.tsx
index 76bc6b91b..995c80517 100644
--- a/client/src/components/Settings/DisplaySettingsTab.tsx
+++ b/client/src/components/Settings/DisplaySettingsTab.tsx
@@ -50,7 +50,7 @@ export default function DisplaySettingsTab(): React.ReactElement {
             { value: 'dashboard', label: t('settings.startPageDashboard') },
             { value: 'active_trip', label: t('settings.startPageActiveTrip') },
           ] as const).map(opt => (
-            <button
+            <button type="button"
               key={opt.value}
               onClick={async () => {
                 try { await updateSetting('start_page', opt.value) }
@@ -117,7 +117,7 @@ export default function DisplaySettingsTab(): React.ReactElement {
         {/* Desktop: Button grid */}
         <div className="hidden sm:flex flex-wrap gap-3">
           {SUPPORTED_LANGUAGES.map(opt => (
-            <button
+            <button type="button"
               key={opt.value}
               onClick={async () => {
                 try { await updateSetting('language', opt.value) }
@@ -201,7 +201,7 @@ export default function DisplaySettingsTab(): React.ReactElement {
             { value: 'celsius', label: '°C Celsius' },
             { value: 'fahrenheit', label: '°F Fahrenheit' },
           ].map(opt => (
-            <button
+            <button type="button"
               key={opt.value}
               onClick={async () => {
                 setTempUnit(opt.value)
@@ -232,7 +232,7 @@ export default function DisplaySettingsTab(): React.ReactElement {
             { value: 'metric', label: 'km Metric' },
             { value: 'imperial', label: 'mi Imperial' },
           ] as const).map(opt => (
-            <button
+            <button type="button"
               key={opt.value}
               onClick={async () => {
                 setDistanceUnit(opt.value)
@@ -263,7 +263,7 @@ export default function DisplaySettingsTab(): React.ReactElement {
             { value: '24h', short: '24h', example: '14:30' },
             { value: '12h', short: '12h', example: '2:30 PM' },
           ].map(opt => (
-            <button
+            <button type="button"
               key={opt.value}
               onClick={async () => {
                 try { await updateSetting('time_format', opt.value) }
@@ -296,7 +296,7 @@ export default function DisplaySettingsTab(): React.ReactElement {
             { value: true, label: t('settings.on') || 'On' },
             { value: false, label: t('settings.off') || 'Off' },
           ].map(opt => (
-            <button
+            <button type="button"
               key={String(opt.value)}
               onClick={async () => {
                 try { await updateSetting('map_booking_labels', opt.value) }
@@ -327,7 +327,7 @@ export default function DisplaySettingsTab(): React.ReactElement {
             { value: true, label: t('settings.on') || 'On' },
             { value: false, label: t('settings.off') || 'Off' },
           ].map(opt => (
-            <button
+            <button type="button"
               key={String(opt.value)}
               onClick={async () => {
                 try { await updateSetting('map_always_show_routes', opt.value) }
@@ -358,7 +358,7 @@ export default function DisplaySettingsTab(): React.ReactElement {
             { value: true, label: t('settings.on') || 'On' },
             { value: false, label: t('settings.off') || 'Off' },
           ].map(opt => (
-            <button
+            <button type="button"
               key={String(opt.value)}
               onClick={async () => {
                 try { await updateSetting('map_poi_pill_enabled', opt.value) }
@@ -389,7 +389,7 @@ export default function DisplaySettingsTab(): React.ReactElement {
             { value: true, label: t('settings.on') || 'On' },
             { value: false, label: t('settings.off') || 'Off' },
           ].map(opt => (
-            <button
+            <button type="button"
               key={String(opt.value)}
               onClick={async () => {
                 try { await updateSetting('blur_booking_codes', opt.value) }
@@ -419,7 +419,7 @@ export default function DisplaySettingsTab(): React.ReactElement {
             { value: true, label: t('settings.on') || 'On' },
             { value: false, label: t('settings.off') || 'Off' },
           ].map(opt => (
-            <button
+            <button type="button"
               key={String(opt.value)}
               onClick={async () => {
                 try { await updateSetting('optimize_from_accommodation', opt.value) }
diff --git a/client/src/components/Settings/IntegrationsTab.tsx b/client/src/components/Settings/IntegrationsTab.tsx
index 8a4654404..9af43a975 100644
--- a/client/src/components/Settings/IntegrationsTab.tsx
+++ b/client/src/components/Settings/IntegrationsTab.tsx
@@ -320,7 +320,7 @@ function IntegrationsMcpSection(props: any) {
               <code className="flex-1 px-3 py-2 rounded-lg text-sm font-mono border bg-surface-secondary border-edge text-content">
                 {mcpEndpoint}
               </code>
-              <button onClick={() => handleCopy(mcpEndpoint, 'endpoint')}
+              <button type="button" onClick={() => handleCopy(mcpEndpoint, 'endpoint')}
                 className="p-2 rounded-lg border border-edge transition-colors hover:bg-slate-100 dark:hover:bg-slate-700"
                 title={t('settings.mcp.copy')}>
                 {copiedKey === 'endpoint' ? <Check className="w-4 h-4 text-green-500" /> : <Copy className="w-4 h-4 text-content-secondary" />}
@@ -330,14 +330,14 @@ function IntegrationsMcpSection(props: any) {
 
           {/* Sub-tab bar */}
           <div className="flex gap-1 rounded-lg p-1 border bg-surface-secondary border-edge">
-            <button
+            <button type="button"
               onClick={() => setActiveMcpTab('oauth')}
               className={`flex-1 px-3 py-1.5 text-sm font-medium rounded-md transition-colors ${
                 activeMcpTab === 'oauth' ? 'bg-slate-900 text-white' : 'text-slate-600 hover:text-slate-900 hover:bg-slate-50'
               }`}>
               {t('settings.oauth.clients')}
             </button>
-            <button
+            <button type="button"
               onClick={() => setActiveMcpTab('apitokens')}
               className={`flex-1 px-3 py-1.5 text-sm font-medium rounded-md transition-colors flex items-center justify-center gap-2 ${
                 activeMcpTab === 'apitokens' ? 'bg-slate-900 text-white' : 'text-slate-600 hover:text-slate-900 hover:bg-slate-50'
@@ -354,7 +354,7 @@ function IntegrationsMcpSection(props: any) {
             <>
               {/* JSON config — OAuth (collapsible) */}
               <div className="rounded-lg border overflow-hidden border-edge">
-                <button
+                <button type="button"
                   onClick={() => setConfigOpenOAuth(o => !o)}
                   className="w-full flex items-center justify-between px-3 py-2.5 transition-colors hover:bg-slate-50 dark:hover:bg-slate-800 bg-surface-secondary">
                   <span className="text-sm font-medium text-content-secondary">{t('settings.mcp.clientConfig')}</span>
@@ -363,7 +363,7 @@ function IntegrationsMcpSection(props: any) {
                 {configOpenOAuth && (
                   <div className="p-3 border-t border-edge">
                     <div className="flex justify-end mb-1.5">
-                      <button onClick={() => handleCopy(mcpJsonConfigOAuth, 'json-oauth')}
+                      <button type="button" onClick={() => handleCopy(mcpJsonConfigOAuth, 'json-oauth')}
                         className="flex items-center gap-1.5 px-2.5 py-1 rounded text-xs border transition-colors hover:bg-slate-100 dark:hover:bg-slate-700 border-edge text-content-secondary">
                         {copiedKey === 'json-oauth' ? <Check className="w-3 h-3 text-green-500" /> : <Copy className="w-3 h-3" />}
                         {copiedKey === 'json-oauth' ? t('settings.mcp.copied') : t('settings.mcp.copy')}
@@ -381,7 +381,7 @@ function IntegrationsMcpSection(props: any) {
                 <p className="text-xs mb-3" style={{ color: 'var(--text-tertiary)' }}>{t('settings.oauth.clientsHint')}</p>
 
                 <div className="flex justify-end mb-2">
-                  <button onClick={() => { setOauthCreateOpen(true); setOauthCreatedClient(null); setOauthNewName(''); setOauthNewUris(''); setOauthNewScopes([]); setOauthIsMachine(false) }}
+                  <button type="button" onClick={() => { setOauthCreateOpen(true); setOauthCreatedClient(null); setOauthNewName(''); setOauthNewUris(''); setOauthNewScopes([]); setOauthIsMachine(false) }}
                     className="flex items-center gap-1.5 px-3 py-1.5 rounded-lg text-sm font-medium transition-colors bg-slate-900 text-white hover:bg-slate-700">
                     <Plus className="w-3.5 h-3.5" /> {t('settings.oauth.createClient')}
                   </button>
@@ -424,12 +424,12 @@ function IntegrationsMcpSection(props: any) {
                               )}
                             </div>
                           </div>
-                          <button onClick={() => setOauthRotateId(client.id)}
+                          <button type="button" onClick={() => setOauthRotateId(client.id)}
                             className="p-1.5 rounded-lg transition-colors hover:bg-amber-50 hover:text-amber-600 dark:hover:bg-amber-900/20"
                             style={{ color: 'var(--text-tertiary)' }} title={t('settings.oauth.rotateSecret')}>
                             <RefreshCw className="w-4 h-4" />
                           </button>
-                          <button onClick={() => setOauthDeleteId(client.id)}
+                          <button type="button" onClick={() => setOauthDeleteId(client.id)}
                             className="p-1.5 rounded-lg transition-colors hover:bg-red-50 hover:text-red-600 dark:hover:bg-red-900/20"
                             style={{ color: 'var(--text-tertiary)' }} title={t('settings.oauth.deleteClient')}>
                             <Trash2 className="w-4 h-4" />
@@ -455,7 +455,7 @@ function IntegrationsMcpSection(props: any) {
                             <span className="ml-3">{t('settings.oauth.sessionExpires')} {new Date(session.access_token_expires_at).toLocaleDateString(locale)}</span>
                           </p>
                         </div>
-                        <button onClick={() => setOauthRevokeId(session.id)}
+                        <button type="button" onClick={() => setOauthRevokeId(session.id)}
                           className="px-2.5 py-1 rounded text-xs border transition-colors hover:bg-red-50 hover:text-red-600 dark:hover:bg-red-900/20 border-edge"
                           style={{ color: 'var(--text-tertiary)' }}>
                           {t('settings.oauth.revoke')}
@@ -478,7 +478,7 @@ function IntegrationsMcpSection(props: any) {
 
               {/* JSON config — API Token (collapsible) */}
               <div className="rounded-lg border overflow-hidden border-edge">
-                <button
+                <button type="button"
                   onClick={() => setConfigOpenToken(o => !o)}
                   className="w-full flex items-center justify-between px-3 py-2.5 transition-colors hover:bg-slate-50 dark:hover:bg-slate-800 bg-surface-secondary">
                   <span className="text-sm font-medium text-content-secondary">{t('settings.mcp.clientConfig')}</span>
@@ -487,7 +487,7 @@ function IntegrationsMcpSection(props: any) {
                 {configOpenToken && (
                   <div className="p-3 border-t border-edge">
                     <div className="flex justify-end mb-1.5">
-                      <button onClick={() => handleCopy(mcpJsonConfig, 'json-token')}
+                      <button type="button" onClick={() => handleCopy(mcpJsonConfig, 'json-token')}
                         className="flex items-center gap-1.5 px-2.5 py-1 rounded text-xs border transition-colors hover:bg-slate-100 dark:hover:bg-slate-700 border-edge text-content-secondary">
                         {copiedKey === 'json-token' ? <Check className="w-3 h-3 text-green-500" /> : <Copy className="w-3 h-3" />}
                         {copiedKey === 'json-token' ? t('settings.mcp.copied') : t('settings.mcp.copy')}
@@ -502,7 +502,7 @@ function IntegrationsMcpSection(props: any) {
               </div>
 
               <div className="flex justify-end">
-                <button onClick={() => { setMcpModalOpen(true); setMcpCreatedToken(null); setMcpNewName('') }}
+                <button type="button" onClick={() => { setMcpModalOpen(true); setMcpCreatedToken(null); setMcpNewName('') }}
                   className="flex items-center gap-1.5 px-3 py-1.5 rounded-lg text-sm font-medium transition-colors opacity-60 text-content-secondary bg-surface-tertiary">
                   <Plus className="w-3.5 h-3.5" /> {t('settings.mcp.createToken')}
                 </button>
@@ -526,7 +526,7 @@ function IntegrationsMcpSection(props: any) {
                           )}
                         </p>
                       </div>
-                      <button onClick={() => setMcpDeleteId(token.id)}
+                      <button type="button" onClick={() => setMcpDeleteId(token.id)}
                         className="p-1.5 rounded-lg transition-colors hover:bg-red-50 hover:text-red-600 dark:hover:bg-red-900/20"
                         style={{ color: 'var(--text-tertiary)' }} title={t('settings.mcp.deleteTokenTitle')}>
                         <Trash2 className="w-4 h-4" />
@@ -564,11 +564,11 @@ function McpTokenModals(props: any) {
                     autoFocus />
                 </div>
                 <div className="flex gap-2 justify-end pt-1">
-                  <button onClick={() => setMcpModalOpen(false)}
+                  <button type="button" onClick={() => setMcpModalOpen(false)}
                     className="px-4 py-2 rounded-lg text-sm border border-edge text-content-secondary">
                     {t('common.cancel')}
                   </button>
-                  <button onClick={handleCreateMcpToken} disabled={!mcpNewName.trim() || mcpCreating}
+                  <button type="button" onClick={handleCreateMcpToken} disabled={!mcpNewName.trim() || mcpCreating}
                     className="px-4 py-2 rounded-lg text-sm font-medium text-white bg-slate-900 hover:bg-slate-700 disabled:opacity-50">
                     {mcpCreating ? t('settings.mcp.modal.creating') : t('settings.mcp.modal.create')}
                   </button>
@@ -585,14 +585,14 @@ function McpTokenModals(props: any) {
                   <pre className="p-3 pr-10 rounded-lg text-xs font-mono break-all border whitespace-pre-wrap bg-surface-secondary border-edge text-content">
                     {mcpCreatedToken}
                   </pre>
-                  <button onClick={() => handleCopy(mcpCreatedToken, 'new-token')}
+                  <button type="button" onClick={() => handleCopy(mcpCreatedToken, 'new-token')}
                     className="absolute top-2 right-2 p-1.5 rounded transition-colors hover:bg-slate-200 dark:hover:bg-slate-600 text-content-secondary"
                     title={t('settings.mcp.copy')}>
                     {copiedKey === 'new-token' ? <Check className="w-4 h-4 text-green-500" /> : <Copy className="w-4 h-4" />}
                   </button>
                 </div>
                 <div className="flex justify-end">
-                  <button onClick={() => { setMcpModalOpen(false); setMcpCreatedToken(null) }}
+                  <button type="button" onClick={() => { setMcpModalOpen(false); setMcpCreatedToken(null) }}
                     className="px-4 py-2 rounded-lg text-sm font-medium text-white bg-slate-900 hover:bg-slate-700">
                     {t('settings.mcp.modal.done')}
                   </button>
@@ -611,11 +611,11 @@ function McpTokenModals(props: any) {
             <h3 className="text-base font-semibold text-content">{t('settings.mcp.deleteTokenTitle')}</h3>
             <p className="text-sm text-content-secondary">{t('settings.mcp.deleteTokenMessage')}</p>
             <div className="flex gap-2 justify-end">
-              <button onClick={() => setMcpDeleteId(null)}
+              <button type="button" onClick={() => setMcpDeleteId(null)}
                 className="px-4 py-2 rounded-lg text-sm border border-edge text-content-secondary">
                 {t('common.cancel')}
               </button>
-              <button onClick={() => handleDeleteMcpToken(mcpDeleteId)}
+              <button type="button" onClick={() => handleDeleteMcpToken(mcpDeleteId)}
                 className="px-4 py-2 rounded-lg text-sm font-medium text-white bg-red-600 hover:bg-red-700">
                 {t('settings.mcp.deleteTokenTitle')}
               </button>
@@ -697,11 +697,11 @@ function OAuthClientModals(props: any) {
                 </div>
 
                 <div className="flex gap-2 justify-end pt-1">
-                  <button onClick={() => setOauthCreateOpen(false)}
+                  <button type="button" onClick={() => setOauthCreateOpen(false)}
                     className="px-4 py-2 rounded-lg text-sm border border-edge text-content-secondary">
                     {t('common.cancel')}
                   </button>
-                  <button onClick={handleCreateOAuthClient}
+                  <button type="button" onClick={handleCreateOAuthClient}
                     disabled={!oauthNewName.trim() || (!oauthIsMachine && !oauthNewUris.trim()) || oauthCreating}
                     className="px-4 py-2 rounded-lg text-sm font-medium text-white bg-slate-900 hover:bg-slate-700 disabled:opacity-50">
                     {oauthCreating ? t('settings.oauth.modal.creating') : t('settings.oauth.modal.create')}
@@ -723,7 +723,7 @@ function OAuthClientModals(props: any) {
                       <code className="flex-1 px-3 py-2 rounded-lg text-xs font-mono border bg-surface-secondary border-edge text-content">
                         {oauthCreatedClient.client_id}
                       </code>
-                      <button onClick={() => handleCopy(oauthCreatedClient.client_id, 'new-client-id')}
+                      <button type="button" onClick={() => handleCopy(oauthCreatedClient.client_id, 'new-client-id')}
                         className="p-2 rounded-lg border transition-colors hover:bg-slate-100 dark:hover:bg-slate-700 border-edge">
                         {copiedKey === 'new-client-id' ? <Check className="w-4 h-4 text-green-500" /> : <Copy className="w-4 h-4 text-content-secondary" />}
                       </button>
@@ -735,7 +735,7 @@ function OAuthClientModals(props: any) {
                       <code className="flex-1 px-3 py-2 rounded-lg text-xs font-mono border break-all bg-surface-secondary border-edge text-content">
                         {oauthCreatedClient.client_secret}
                       </code>
-                      <button onClick={() => handleCopy(oauthCreatedClient.client_secret!, 'new-client-secret')}
+                      <button type="button" onClick={() => handleCopy(oauthCreatedClient.client_secret!, 'new-client-secret')}
                         className="p-2 rounded-lg border transition-colors hover:bg-slate-100 dark:hover:bg-slate-700 border-edge">
                         {copiedKey === 'new-client-secret' ? <Check className="w-4 h-4 text-green-500" /> : <Copy className="w-4 h-4 text-content-secondary" />}
                       </button>
@@ -750,7 +750,7 @@ function OAuthClientModals(props: any) {
                 )}
 
                 <div className="flex justify-end">
-                  <button onClick={() => { setOauthCreateOpen(false); setOauthCreatedClient(null) }}
+                  <button type="button" onClick={() => { setOauthCreateOpen(false); setOauthCreatedClient(null) }}
                     className="px-4 py-2 rounded-lg text-sm font-medium text-white bg-slate-900 hover:bg-slate-700">
                     {t('settings.mcp.modal.done')}
                   </button>
@@ -769,11 +769,11 @@ function OAuthClientModals(props: any) {
             <h3 className="text-base font-semibold text-content">{t('settings.oauth.deleteClient')}</h3>
             <p className="text-sm text-content-secondary">{t('settings.oauth.deleteClientMessage')}</p>
             <div className="flex gap-2 justify-end">
-              <button onClick={() => setOauthDeleteId(null)}
+              <button type="button" onClick={() => setOauthDeleteId(null)}
                 className="px-4 py-2 rounded-lg text-sm border border-edge text-content-secondary">
                 {t('common.cancel')}
               </button>
-              <button onClick={() => handleDeleteOAuthClient(oauthDeleteId)}
+              <button type="button" onClick={() => handleDeleteOAuthClient(oauthDeleteId)}
                 className="px-4 py-2 rounded-lg text-sm font-medium text-white bg-red-600 hover:bg-red-700">
                 {t('settings.oauth.deleteClient')}
               </button>
@@ -790,11 +790,11 @@ function OAuthClientModals(props: any) {
             <h3 className="text-base font-semibold text-content">{t('settings.oauth.rotateSecret')}</h3>
             <p className="text-sm text-content-secondary">{t('settings.oauth.rotateSecretMessage')}</p>
             <div className="flex gap-2 justify-end">
-              <button onClick={() => setOauthRotateId(null)}
+              <button type="button" onClick={() => setOauthRotateId(null)}
                 className="px-4 py-2 rounded-lg text-sm border border-edge text-content-secondary">
                 {t('common.cancel')}
               </button>
-              <button onClick={() => handleRotateSecret(oauthRotateId)} disabled={oauthRotating}
+              <button type="button" onClick={() => handleRotateSecret(oauthRotateId)} disabled={oauthRotating}
                 className="px-4 py-2 rounded-lg text-sm font-medium text-white bg-slate-900 hover:bg-slate-700 disabled:opacity-50">
                 {oauthRotating ? t('settings.oauth.rotateSecretConfirming') : t('settings.oauth.rotateSecretConfirm')}
               </button>
@@ -818,14 +818,14 @@ function OAuthClientModals(props: any) {
                 <code className="flex-1 px-3 py-2 rounded-lg text-xs font-mono border break-all bg-surface-secondary border-edge text-content">
                   {oauthRotatedSecret}
                 </code>
-                <button onClick={() => handleCopy(oauthRotatedSecret, 'rotated-secret')}
+                <button type="button" onClick={() => handleCopy(oauthRotatedSecret, 'rotated-secret')}
                   className="p-2 rounded-lg border transition-colors hover:bg-slate-100 dark:hover:bg-slate-700 border-edge">
                   {copiedKey === 'rotated-secret' ? <Check className="w-4 h-4 text-green-500" /> : <Copy className="w-4 h-4 text-content-secondary" />}
                 </button>
               </div>
             </div>
             <div className="flex justify-end">
-              <button onClick={() => setOauthRotatedSecret(null)}
+              <button type="button" onClick={() => setOauthRotatedSecret(null)}
                 className="px-4 py-2 rounded-lg text-sm font-medium text-white bg-slate-900 hover:bg-slate-700">
                 {t('settings.mcp.modal.done')}
               </button>
@@ -842,11 +842,11 @@ function OAuthClientModals(props: any) {
             <h3 className="text-base font-semibold text-content">{t('settings.oauth.revokeSession')}</h3>
             <p className="text-sm text-content-secondary">{t('settings.oauth.revokeSessionMessage')}</p>
             <div className="flex gap-2 justify-end">
-              <button onClick={() => setOauthRevokeId(null)}
+              <button type="button" onClick={() => setOauthRevokeId(null)}
                 className="px-4 py-2 rounded-lg text-sm border border-edge text-content-secondary">
                 {t('common.cancel')}
               </button>
-              <button onClick={() => handleRevokeSession(oauthRevokeId)}
+              <button type="button" onClick={() => handleRevokeSession(oauthRevokeId)}
                 className="px-4 py-2 rounded-lg text-sm font-medium text-white bg-red-600 hover:bg-red-700">
                 {t('settings.oauth.revoke')}
               </button>
diff --git a/client/src/components/Settings/LlmConnectionSection.tsx b/client/src/components/Settings/LlmConnectionSection.tsx
index 67e8bcf92..bd1841655 100644
--- a/client/src/components/Settings/LlmConnectionSection.tsx
+++ b/client/src/components/Settings/LlmConnectionSection.tsx
@@ -143,7 +143,7 @@ export default function LlmConnectionSection(): React.ReactElement {
           <p className="mt-1 text-xs text-content-faint">{t('settings.aiParsing.multimodalHint')}</p>
         </div>
 
-        <button
+        <button type="button"
           onClick={handleSave}
           disabled={saving || !isLoaded}
           className="flex items-center gap-2 px-4 py-2 rounded-lg text-sm font-medium text-white bg-slate-900 hover:bg-slate-700 disabled:opacity-50"
diff --git a/client/src/components/Settings/MapSettingsTab.tsx b/client/src/components/Settings/MapSettingsTab.tsx
index 131381bd2..97e3e599e 100644
--- a/client/src/components/Settings/MapSettingsTab.tsx
+++ b/client/src/components/Settings/MapSettingsTab.tsx
@@ -449,7 +449,7 @@ export default function MapSettingsTab(): React.ReactElement {
         </div>
       </div>
 
-      <button
+      <button type="button"
         onClick={saveMapSettings}
         disabled={saving}
         className="flex items-center gap-2 px-4 py-2 bg-slate-900 text-white rounded-lg text-sm hover:bg-slate-700 disabled:bg-slate-400"
diff --git a/client/src/components/Settings/NotificationsTab.tsx b/client/src/components/Settings/NotificationsTab.tsx
index f59e60895..9a1fb2b71 100644
--- a/client/src/components/Settings/NotificationsTab.tsx
+++ b/client/src/components/Settings/NotificationsTab.tsx
@@ -243,14 +243,14 @@ export default function NotificationsTab(): React.ReactElement {
                 placeholder={webhookIsSet ? '••••••••' : t('settings.webhookUrl.placeholder')}
                 style={{ flex: 1, fontSize: 'calc(13px * var(--fs-scale-body, 1))', padding: '6px 10px', border: '1px solid var(--border-primary)', borderRadius: 6, background: 'var(--bg-primary)', color: 'var(--text-primary)' }}
               />
-              <button
+              <button type="button"
                 onClick={saveWebhookUrl}
                 disabled={webhookSaving}
                 style={{ fontSize: 'calc(12px * var(--fs-scale-body, 1))', padding: '6px 12px', background: 'var(--text-primary)', color: 'var(--bg-primary)', border: 'none', borderRadius: 6, cursor: webhookSaving ? 'not-allowed' : 'pointer', opacity: webhookSaving ? 0.6 : 1 }}
               >
                 {t('common.save')}
               </button>
-              <button
+              <button type="button"
                 onClick={testWebhookUrl}
                 disabled={(!webhookUrl && !webhookIsSet) || webhookTesting}
                 style={{ fontSize: 'calc(12px * var(--fs-scale-body, 1))', padding: '6px 12px', background: 'transparent', color: 'var(--text-secondary)', border: '1px solid var(--border-primary)', borderRadius: 6, cursor: ((!webhookUrl && !webhookIsSet) || webhookTesting) ? 'not-allowed' : 'pointer', opacity: ((!webhookUrl && !webhookIsSet) || webhookTesting) ? 0.5 : 1 }}
@@ -296,21 +296,21 @@ export default function NotificationsTab(): React.ReactElement {
                 style={{ flex: 1, fontSize: 'calc(13px * var(--fs-scale-body, 1))', padding: '6px 10px', border: '1px solid var(--border-primary)', borderRadius: 6, background: 'var(--bg-primary)', color: 'var(--text-primary)' }}
               />
               {ntfyTokenIsSet && (
-                <button
+                <button type="button"
                   onClick={clearNtfyToken}
                   style={{ fontSize: 'calc(12px * var(--fs-scale-body, 1))', padding: '6px 12px', background: 'transparent', color: 'var(--color-danger, #e53e3e)', border: '1px solid var(--color-danger, #e53e3e)', borderRadius: 6, cursor: 'pointer' }}
                 >
                   {t('common.clear')}
                 </button>
               )}
-              <button
+              <button type="button"
                 onClick={saveNtfySettings}
                 disabled={ntfySaving}
                 style={{ fontSize: 'calc(12px * var(--fs-scale-body, 1))', padding: '6px 12px', background: 'var(--text-primary)', color: 'var(--bg-primary)', border: 'none', borderRadius: 6, cursor: ntfySaving ? 'not-allowed' : 'pointer', opacity: ntfySaving ? 0.6 : 1 }}
               >
                 {t('common.save')}
               </button>
-              <button
+              <button type="button"
                 onClick={testNtfySettings}
                 disabled={!ntfyTopic || ntfyTesting}
                 style={{ fontSize: 'calc(12px * var(--fs-scale-body, 1))', padding: '6px 12px', background: 'transparent', color: 'var(--text-secondary)', border: '1px solid var(--border-primary)', borderRadius: 6, cursor: (!ntfyTopic || ntfyTesting) ? 'not-allowed' : 'pointer', opacity: (!ntfyTopic || ntfyTesting) ? 0.5 : 1 }}
@@ -341,7 +341,7 @@ export default function NotificationsTab(): React.ReactElement {
                   {t('settings.notificationPreferences.configure')}
                 </Link>
               )}
-              <button
+              <button type="button"
                 onClick={() => testChannel(ch)}
                 disabled={!ch.configured || channelTesting === ch.id}
                 style={{ fontSize: 'calc(12px * var(--fs-scale-body, 1))', padding: '6px 12px', background: 'transparent', color: 'var(--text-secondary)', border: '1px solid var(--border-primary)', borderRadius: 6, cursor: (!ch.configured || channelTesting === ch.id) ? 'not-allowed' : 'pointer', opacity: (!ch.configured || channelTesting === ch.id) ? 0.5 : 1 }}
diff --git a/client/src/components/Settings/OfflineTab.tsx b/client/src/components/Settings/OfflineTab.tsx
index 40cf63dba..5c950b234 100644
--- a/client/src/components/Settings/OfflineTab.tsx
+++ b/client/src/components/Settings/OfflineTab.tsx
@@ -202,7 +202,7 @@ export default function OfflineTab(): React.ReactElement {
               {t('settings.offline.prepare.hint')}
             </p>
             <div style={{ display: 'flex', gap: 8, alignItems: 'center', flexWrap: 'wrap' }}>
-              <button
+              <button type="button"
                 onClick={runPrepare}
                 disabled={preparing || offline}
                 className="border border-edge bg-surface-secondary text-content"
@@ -213,7 +213,7 @@ export default function OfflineTab(): React.ReactElement {
                   : <Download size={14} />}
                 {preparing ? t('settings.offline.prepare.running') : t('settings.offline.prepare.button')}
               </button>
-              <button
+              <button type="button"
                 onClick={handleResync}
                 disabled={syncing || offline}
                 className="border border-edge bg-surface-secondary text-content"
@@ -259,10 +259,10 @@ export default function OfflineTab(): React.ReactElement {
                   {t('settings.offline.conflicts.item', { name: conflictName(c) })}
                 </span>
                 <div style={{ display: 'flex', gap: 8 }}>
-                  <button onClick={() => resolveConflict(c.id, true)} className="border border-edge bg-surface-card text-content" style={smallBtnStyle()}>
+                  <button type="button" onClick={() => resolveConflict(c.id, true)} className="border border-edge bg-surface-card text-content" style={smallBtnStyle()}>
                     {t('settings.offline.conflicts.keepMine')}
                   </button>
-                  <button onClick={() => resolveConflict(c.id, false)} className="border border-edge bg-surface-card text-content" style={smallBtnStyle()}>
+                  <button type="button" onClick={() => resolveConflict(c.id, false)} className="border border-edge bg-surface-card text-content" style={smallBtnStyle()}>
                     {t('settings.offline.conflicts.keepServer')}
                   </button>
                 </div>
@@ -334,7 +334,7 @@ export default function OfflineTab(): React.ReactElement {
           </div>
 
           <div style={{ display: 'flex', gap: 8 }}>
-            <button
+            <button type="button"
               onClick={handleClear}
               disabled={clearing || rows.length === 0}
               className="border border-edge bg-surface-secondary text-[#ef4444]"
diff --git a/client/src/components/Settings/PhotoProvidersSection.tsx b/client/src/components/Settings/PhotoProvidersSection.tsx
index c36fce449..139433dde 100644
--- a/client/src/components/Settings/PhotoProvidersSection.tsx
+++ b/client/src/components/Settings/PhotoProvidersSection.tsx
@@ -253,7 +253,7 @@ export default function PhotoProvidersSection(): React.ReactElement {
           {/* Wraps on mobile so the connection badge drops to its own row
               instead of clipping off the side of the card. */}
           <div className="flex flex-wrap items-center gap-3">
-            <button
+            <button type="button"
               onClick={() => handleSaveProvider(provider)}
               disabled={!canSave || !!saving[provider.id] || isProviderSaveDisabled(provider)}
               className="flex items-center gap-2 px-4 py-2 bg-slate-900 text-white rounded-lg text-sm hover:bg-slate-700 disabled:bg-slate-400"
@@ -261,7 +261,7 @@ export default function PhotoProvidersSection(): React.ReactElement {
             >
               <Save className="w-4 h-4" /> {t('common.save')}
             </button>
-            <button
+            <button type="button"
               onClick={() => handleTestProvider(provider)}
               disabled={!canTest || testing}
               className="flex items-center gap-2 px-4 py-2 border border-slate-200 rounded-lg text-sm hover:bg-slate-50"
diff --git a/client/src/components/Settings/PluginSettingsTab.tsx b/client/src/components/Settings/PluginSettingsTab.tsx
index 638054c1f..25d24499b 100644
--- a/client/src/components/Settings/PluginSettingsTab.tsx
+++ b/client/src/components/Settings/PluginSettingsTab.tsx
@@ -45,8 +45,8 @@ function PluginOAuthSection({ id, state, setState }: {
           : <>{t('settings.plugins.oauth.notConnected')}</>}
       </span>
       {state.connected
-        ? <button onClick={disconnect} disabled={busy} className="inline-flex items-center gap-1.5 rounded-lg border border-border px-3 py-1.5 text-sm font-semibold text-content disabled:opacity-60"><Unlink className="w-4 h-4" />{t('settings.plugins.oauth.disconnect')}</button>
-        : <button onClick={connect} disabled={busy} className="inline-flex items-center gap-1.5 rounded-lg bg-accent px-3 py-1.5 text-sm font-semibold text-white disabled:opacity-60">{busy ? <Loader2 className="w-4 h-4 animate-spin" /> : <Link2 className="w-4 h-4" />}{t('settings.plugins.oauth.connect')}</button>}
+        ? <button type="button" onClick={disconnect} disabled={busy} className="inline-flex items-center gap-1.5 rounded-lg border border-border px-3 py-1.5 text-sm font-semibold text-content disabled:opacity-60"><Unlink className="w-4 h-4" />{t('settings.plugins.oauth.disconnect')}</button>
+        : <button type="button" onClick={connect} disabled={busy} className="inline-flex items-center gap-1.5 rounded-lg bg-accent px-3 py-1.5 text-sm font-semibold text-white disabled:opacity-60">{busy ? <Loader2 className="w-4 h-4 animate-spin" /> : <Link2 className="w-4 h-4" />}{t('settings.plugins.oauth.connect')}</button>}
     </div>
   )
 }
@@ -176,7 +176,7 @@ function PluginSettingsForm({ id, name, icon }: { id: string; name: string; icon
         ))}
       </div>
       {hasFields && (
-        <button
+        <button type="button"
           onClick={save}
           disabled={saving}
           className="mt-4 inline-flex items-center gap-2 rounded-lg bg-accent px-4 py-2 text-sm font-semibold text-white disabled:opacity-60"
@@ -195,7 +195,7 @@ function PluginSettingsForm({ id, name, icon }: { id: string; name: string; icon
               const res = actionResult[a.key]
               return (
                 <div key={a.key} className="flex flex-wrap items-center gap-2">
-                  <button
+                  <button type="button"
                     onClick={() => runAction(a)}
                     disabled={running !== null}
                     className={`inline-flex items-center gap-2 rounded-lg border px-3 py-1.5 text-sm font-semibold disabled:opacity-60 ${
diff --git a/client/src/components/Studio/SaveIndicator.tsx b/client/src/components/Studio/SaveIndicator.tsx
index e0a9fe8a7..4f44c37ce 100644
--- a/client/src/components/Studio/SaveIndicator.tsx
+++ b/client/src/components/Studio/SaveIndicator.tsx
@@ -33,10 +33,10 @@ export function SaveIndicator({
           pretending otherwise would be worse than saying so: one of these
           documents is going to be the book.
         */}
-        <button onClick={() => onAcceptTheirs(state.current)}>
+        <button type="button" onClick={() => onAcceptTheirs(state.current)}>
           {t('journey.studio.saveTakeTheirs')}
         </button>
-        <button onClick={() => onKeepMine(state.current)}>
+        <button type="button" onClick={() => onKeepMine(state.current)}>
           {t('journey.studio.saveKeepMine')}
         </button>
       </div>
@@ -59,7 +59,7 @@ export function SaveIndicator({
 
   if (state.status === 'error') {
     return (
-      <button className="st-save is-error" onClick={onRetry} title={t('journey.studio.saveRetry')}>
+      <button type="button" className="st-save is-error" onClick={onRetry} title={t('journey.studio.saveRetry')}>
         <CloudOff size={13} />
         <span>{t('journey.studio.saveFailed')}</span>
       </button>
diff --git a/client/src/components/Studio/SpreadView.tsx b/client/src/components/Studio/SpreadView.tsx
index d5440e853..182e8957f 100644
--- a/client/src/components/Studio/SpreadView.tsx
+++ b/client/src/components/Studio/SpreadView.tsx
@@ -38,7 +38,7 @@ const round2 = (n: number) => Math.round(n * 100) / 100
 
 /** #rrggbb plus an alpha, for the fades a cover panel needs. */
 function hexToRgba(hex: string, alpha: number): string {
-  const n = parseInt(hex.slice(1), 16)
+  const n = Number.parseInt(hex.slice(1), 16)
   return `rgba(${(n >> 16) & 255}, ${(n >> 8) & 255}, ${n & 255}, ${alpha})`
 }
 
diff --git a/client/src/components/Studio/StudioCanvas.tsx b/client/src/components/Studio/StudioCanvas.tsx
index 518b09ce4..eaddd692b 100644
--- a/client/src/components/Studio/StudioCanvas.tsx
+++ b/client/src/components/Studio/StudioCanvas.tsx
@@ -394,15 +394,15 @@ export function StudioCanvas({
               style={{ left: (x0 + x1) / 2, top: Math.max(6, y0 - 12) }}
               onPointerDown={e => e.stopPropagation()}
             >
-              <button onClick={() => duplicate(spreadIndex, selection)} title={t('journey.studio.duplicate')}>
+              <button type="button" onClick={() => duplicate(spreadIndex, selection)} title={t('journey.studio.duplicate')}>
                 <Copy size={14} />
               </button>
               {sel.length === 1 && (
                 <>
-                  <button onClick={() => raise(spreadIndex, sel[0].id, 'front')} title={t('journey.studio.toFront')}>
+                  <button type="button" onClick={() => raise(spreadIndex, sel[0].id, 'front')} title={t('journey.studio.toFront')}>
                     <ChevronsUp size={14} />
                   </button>
-                  <button onClick={() => raise(spreadIndex, sel[0].id, 'back')} title={t('journey.studio.toBack')}>
+                  <button type="button" onClick={() => raise(spreadIndex, sel[0].id, 'back')} title={t('journey.studio.toBack')}>
                     <ChevronsDown size={14} />
                   </button>
                 </>
@@ -417,13 +417,13 @@ export function StudioCanvas({
                 a rotation past the angle you wanted and back is a worse way to
                 arrive at either.
               */}
-              <button
+              <button type="button"
                 onClick={e => rotateBy(e.shiftKey ? -1 : -15)}
                 title={t('journey.studio.rotateLeft')}
               >
                 <RotateCcw size={14} />
               </button>
-              <button
+              <button type="button"
                 onClick={e => rotateBy(e.shiftKey ? 1 : 15)}
                 title={t('journey.studio.rotateRight')}
               >
@@ -443,7 +443,7 @@ export function StudioCanvas({
                 {locked ? <Unlock size={14} /> : <Lock size={14} />}
               </button>
               <span className="st-quickbar-sep" />
-              <button
+              <button type="button"
                 className="is-danger"
                 onClick={() => { const ids = deletable(spread, selection); if (ids.length) removeElements(spreadIndex, ids) }}
                 title={t('journey.studio.delete')}
diff --git a/client/src/components/Studio/StudioControls.tsx b/client/src/components/Studio/StudioControls.tsx
index 95ca427f4..468f8a8b2 100644
--- a/client/src/components/Studio/StudioControls.tsx
+++ b/client/src/components/Studio/StudioControls.tsx
@@ -46,7 +46,7 @@ export function Section({ label, children, defaultOpen = true, hint }: {
   const [open, setOpen] = useState(defaultOpen)
   return (
     <div className={`st-section is-fold ${open ? '' : 'is-folded'}`}>
-      <button className="st-section-head" onClick={() => setOpen(!open)} aria-expanded={open}>
+      <button type="button" className="st-section-head" onClick={() => setOpen(!open)} aria-expanded={open}>
         <span className="st-section-label">{label}</span>
         <ChevronDown size={13} className="st-section-caret" />
       </button>
@@ -85,7 +85,7 @@ export function Choice<T extends string | number>({ value, options, onPick, aria
   return (
     <div className="st-row" role="radiogroup" aria-label={ariaLabel}>
       {options.map(o => (
-        <button
+        <button type="button"
           key={String(o.value)}
           role="radio"
           aria-checked={o.value === value}
@@ -118,7 +118,7 @@ export function Picks<T extends string>({ value, options, onToggle }: {
       {options.map(o => {
         const on = value.includes(o.value)
         return (
-          <button
+          <button type="button"
             key={o.value}
             role="checkbox"
             aria-checked={on}
diff --git a/client/src/components/Studio/StudioElementsPanel.tsx b/client/src/components/Studio/StudioElementsPanel.tsx
index c74ba99f2..cd518ace4 100644
--- a/client/src/components/Studio/StudioElementsPanel.tsx
+++ b/client/src/components/Studio/StudioElementsPanel.tsx
@@ -81,7 +81,7 @@ function FrameStyleGlyph({ style }: { style: FrameStyle }) {
 function IconCell({ name, onPick }: { name: string; onPick: (name: string) => void }) {
   const Icon = iconComponent(name)
   return (
-    <button
+    <button type="button"
       className="st-shape-btn is-glyph"
       onClick={() => onPick(name)}
       aria-label={name}
@@ -216,16 +216,16 @@ export function StudioElementsPanel({ page, t }: { page: BookPageSetup; t: (k: s
       <PanelHead label={t('journey.studio.elements')} />
 
       <div className="st-tabs">
-        <button className={tab === 'shapes' ? 'is-on' : ''} onClick={() => setTab('shapes')}>
+        <button type="button" className={tab === 'shapes' ? 'is-on' : ''} onClick={() => setTab('shapes')}>
           {t('journey.studio.shapes')}
         </button>
-        <button className={tab === 'frames' ? 'is-on' : ''} onClick={() => setTab('frames')}>
+        <button type="button" className={tab === 'frames' ? 'is-on' : ''} onClick={() => setTab('frames')}>
           {t('journey.studio.frames')}
         </button>
-        <button className={tab === 'grids' ? 'is-on' : ''} onClick={() => setTab('grids')}>
+        <button type="button" className={tab === 'grids' ? 'is-on' : ''} onClick={() => setTab('grids')}>
           {t('journey.studio.grids')}
         </button>
-        <button className={tab === 'icons' ? 'is-on' : ''} onClick={() => setTab('icons')}>
+        <button type="button" className={tab === 'icons' ? 'is-on' : ''} onClick={() => setTab('icons')}>
           {t('journey.studio.icons')}
         </button>
       </div>
@@ -236,18 +236,18 @@ export function StudioElementsPanel({ page, t }: { page: BookPageSetup; t: (k: s
             <div className="st-section">
               <div className="st-section-label">{t('journey.studio.text')}</div>
               <div className="st-stack">
-                <button className="st-tile" onClick={() => addText(30, 700, t('journey.studio.sampleHeading'))}>
+                <button type="button" className="st-tile" onClick={() => addText(30, 700, t('journey.studio.sampleHeading'))}>
                   <span style={{ fontSize: 19, fontWeight: 700, letterSpacing: '-0.02em' }}>
                     {t('journey.studio.styleTitle')}
                   </span>
                 </button>
-                <button className="st-tile" onClick={() => addText(16, 600, t('journey.studio.sampleSubheading'))}>
+                <button type="button" className="st-tile" onClick={() => addText(16, 600, t('journey.studio.sampleSubheading'))}>
                   <span style={{ fontSize: 14, fontWeight: 600 }}>{t('journey.studio.styleSubtitle')}</span>
                 </button>
-                <button className="st-tile" onClick={() => addText(10, 400, t('journey.studio.sampleBody'))}>
+                <button type="button" className="st-tile" onClick={() => addText(10, 400, t('journey.studio.sampleBody'))}>
                   <span style={{ fontSize: 12.5 }}>{t('journey.studio.styleBody')}</span>
                 </button>
-                <button
+                <button type="button"
                   className="st-tile"
                   onClick={() => addText(7.5, 600, t('journey.studio.sampleCaption'), { tracking: 0.14, color: '#8a8578' })}
                 >
@@ -261,17 +261,17 @@ export function StudioElementsPanel({ page, t }: { page: BookPageSetup; t: (k: s
             <div className="st-section">
               <div className="st-section-label">{t('journey.studio.lines')}</div>
               <div className="st-shape-grid">
-                <button className="st-shape-btn" onClick={() => addShape('line')} title={t('journey.studio.shapeKind.line')}>
+                <button type="button" className="st-shape-btn" onClick={() => addShape('line')} title={t('journey.studio.shapeKind.line')}>
                   <Minus size={20} strokeWidth={2} />
                 </button>
-                <button
+                <button type="button"
                   className="st-shape-btn"
                   onClick={() => addShape('rect', { outline: true })}
                   title={t('journey.studio.shapeKind.outline')}
                 >
                   <Square size={20} strokeWidth={1.1} style={{ opacity: .5 }} />
                 </button>
-                <button
+                <button type="button"
                   className="st-shape-btn"
                   onClick={() => addText(46, 700, '“', { color: '#c9c2b4', leading: 0.9 })}
                   title={t('journey.studio.quoteMark')}
@@ -286,7 +286,7 @@ export function StudioElementsPanel({ page, t }: { page: BookPageSetup; t: (k: s
                 <div className="st-section-label">{t(`journey.studio.shapeGroup.${group.id}`)}</div>
                 <div className="st-shape-grid">
                   {group.shapes.map(shape => (
-                    <button
+                    <button type="button"
                       key={shape}
                       className="st-shape-btn is-glyph"
                       onClick={() => addShape(shape)}
@@ -314,7 +314,7 @@ export function StudioElementsPanel({ page, t }: { page: BookPageSetup; t: (k: s
                   ['film', 'filmFrame'],
                   ['tape', 'tapeFrame'],
                 ] as [FrameStyle, string][]).map(([style, key]) => (
-                  <button
+                  <button type="button"
                     key={style}
                     className="st-shape-btn is-frame"
                     onClick={() => addFrame(null, style)}
@@ -331,7 +331,7 @@ export function StudioElementsPanel({ page, t }: { page: BookPageSetup; t: (k: s
               <div className="st-section-label">{t('journey.studio.frameShapes')}</div>
               <div className="st-shape-grid">
                 {FRAME_SHAPES.map(shape => (
-                  <button
+                  <button type="button"
                     key={shape}
                     className="st-shape-btn is-glyph"
                     onClick={() => addFrame(shape === 'rect' ? null : shape)}
@@ -408,7 +408,7 @@ export function StudioElementsPanel({ page, t }: { page: BookPageSetup; t: (k: s
                 spellCheck={false}
               />
               {iconQuery && (
-                <button onClick={() => { setIconQuery(''); setIconLimit(ICON_PAGE) }} aria-label={t('common.clear')}>
+                <button type="button" onClick={() => { setIconQuery(''); setIconLimit(ICON_PAGE) }} aria-label={t('common.clear')}>
                   <X size={13} />
                 </button>
               )}
diff --git a/client/src/components/Studio/StudioExport.tsx b/client/src/components/Studio/StudioExport.tsx
index e1c570ba2..c8d90798d 100644
--- a/client/src/components/Studio/StudioExport.tsx
+++ b/client/src/components/Studio/StudioExport.tsx
@@ -81,7 +81,7 @@ export function StudioExport({
       <div className="st-ex-card">
         <div className="st-ex-head">
           <span>{t('journey.studio.export')}</span>
-          <button className="st-ex-x" onClick={onClose} aria-label={t('common.close')}>
+          <button type="button" className="st-ex-x" onClick={onClose} aria-label={t('common.close')}>
             <X size={15} />
           </button>
         </div>
@@ -109,7 +109,7 @@ export function StudioExport({
 
           <div className="st-ex-field">
             <span className="st-ex-label">{t('journey.studio.exportFinishing')}</span>
-            <button
+            <button type="button"
               className={`st-ex-opt ${marks ? 'is-on' : ''}`}
               onClick={() => setMarks(!marks)}
               aria-pressed={marks}
@@ -134,8 +134,8 @@ export function StudioExport({
         </div>
 
         <div className="st-ex-foot">
-          <button className="st-ex-btn" onClick={onClose}>{t('common.cancel')}</button>
-          <button className="st-ex-btn is-primary" onClick={() => setBuilding(true)} disabled={building}>
+          <button type="button" className="st-ex-btn" onClick={onClose}>{t('common.cancel')}</button>
+          <button type="button" className="st-ex-btn is-primary" onClick={() => setBuilding(true)} disabled={building}>
             <Printer size={14} />
             <span>{t('journey.studio.exportOpen')}</span>
           </button>
@@ -176,7 +176,7 @@ function Choice<T extends string>({
     <div className="st-ex-field">
       <span className="st-ex-label">{label}</span>
       {options.map(opt => (
-        <button
+        <button type="button"
           key={opt.id}
           className={`st-ex-opt ${value === opt.id ? 'is-on' : ''}`}
           onClick={() => onPick(opt.id)}
diff --git a/client/src/components/Studio/StudioInspector.tsx b/client/src/components/Studio/StudioInspector.tsx
index 82d1f27d3..45f45539d 100644
--- a/client/src/components/Studio/StudioInspector.tsx
+++ b/client/src/components/Studio/StudioInspector.tsx
@@ -204,7 +204,7 @@ export function StudioInspector({
           {sel.length > 1 && <em>{sel.length}</em>}
         </span>
         <span className="st-head-acts">
-          <button
+          <button type="button"
             className="st-act"
             onClick={() => duplicate(spreadIndex, selection)}
             title={t('journey.studio.duplicate')}
@@ -212,7 +212,7 @@ export function StudioInspector({
           >
             <Copy size={14} />
           </button>
-          <button
+          <button type="button"
             className={`st-act ${el.locked ? 'is-on' : ''}`}
             onClick={() => set({ locked: !el.locked })}
             title={t(el.locked ? 'journey.studio.unlock' : 'journey.studio.lock')}
@@ -221,7 +221,7 @@ export function StudioInspector({
           >
             {el.locked ? <Lock size={14} /> : <Unlock size={14} />}
           </button>
-          <button
+          <button type="button"
             className="st-act is-danger"
             onClick={() => removeElements(spreadIndex, selection)}
             title={t('journey.studio.delete')}
@@ -285,7 +285,7 @@ export function StudioInspector({
                 {BOOK_FONT_ORDER.map(id => {
                   const font = BOOK_FONTS[id]
                   return (
-                    <button
+                    <button type="button"
                       key={id}
                       className={`st-font ${el.font === id ? 'is-on' : ''}`}
                       style={{ fontFamily: font.stack }}
@@ -319,7 +319,7 @@ export function StudioInspector({
                 <Line label={t('journey.studio.align')}>
                   <div className="st-row">
                     {([['left', AlignLeft], ['center', AlignCenter], ['right', AlignRight], ['justify', AlignJustify]] as const).map(([a, Icon]) => (
-                      <button
+                      <button type="button"
                         key={a}
                         className={`st-chip is-icon ${el.align === a ? 'is-on' : ''}`}
                         onClick={() => set({ align: a })}
@@ -331,7 +331,7 @@ export function StudioInspector({
                     {/* Italic sits with the alignment because both are things
                         you do to a line rather than to a typeface. It had no
                         control at all before, though the renderer drew it. */}
-                    <button
+                    <button type="button"
                       className={`st-chip is-icon ${el.italic ? 'is-on' : ''}`}
                       onClick={() => set({ italic: !el.italic })}
                       title={t('journey.studio.italic')}
@@ -450,7 +450,7 @@ export function StudioInspector({
 
             <Section label={t('journey.studio.mask')} defaultOpen={false}>
               <div className="st-mini-shapes">
-                <button
+                <button type="button"
                   className={`st-mini-shape ${el.mask ? '' : 'is-on'}`}
                   onClick={() => set({ mask: null })}
                   title={t('journey.studio.maskNone')}
@@ -458,7 +458,7 @@ export function StudioInspector({
                   <span className="st-mini-none" />
                 </button>
                 {FRAME_SHAPES.filter(sh => sh !== 'rect').map(sh => (
-                  <button
+                  <button type="button"
                     key={sh}
                     className={`st-mini-shape ${el.mask === sh ? 'is-on' : ''}`}
                     onClick={() => set({ mask: sh })}
@@ -480,7 +480,7 @@ export function StudioInspector({
                   deleting and re-adding would not. */}
               <div className="st-mini-shapes">
                 {SHAPE_GROUPS.flatMap(g => g.shapes).map((sh: BookShapeId) => (
-                  <button
+                  <button type="button"
                     key={sh}
                     className={`st-mini-shape ${el.shape === sh ? 'is-on' : ''}`}
                     onClick={() => set({ shape: sh })}
@@ -608,7 +608,7 @@ export function StudioInspector({
                 {iconChoices.map(name => {
                   const Glyph = iconComponent(name)
                   return (
-                    <button
+                    <button type="button"
                       key={name}
                       className={`st-mini-shape ${el.name === name ? 'is-on' : ''}`}
                       onClick={() => set({ name })}
@@ -683,16 +683,16 @@ export function StudioInspector({
 
         <Section label={t('journey.studio.arrange')} defaultOpen={false}>
           <div className="st-row">
-            <button className="st-chip is-icon" onClick={() => raise(spreadIndex, el.id, 'front')} title={t('journey.studio.toFront')}>
+            <button type="button" className="st-chip is-icon" onClick={() => raise(spreadIndex, el.id, 'front')} title={t('journey.studio.toFront')}>
               <ChevronsUp size={14} />
             </button>
-            <button className="st-chip is-icon" onClick={() => raise(spreadIndex, el.id, 'up')} title={t('journey.studio.forward')}>
+            <button type="button" className="st-chip is-icon" onClick={() => raise(spreadIndex, el.id, 'up')} title={t('journey.studio.forward')}>
               <ArrowUp size={14} />
             </button>
-            <button className="st-chip is-icon" onClick={() => raise(spreadIndex, el.id, 'down')} title={t('journey.studio.backward')}>
+            <button type="button" className="st-chip is-icon" onClick={() => raise(spreadIndex, el.id, 'down')} title={t('journey.studio.backward')}>
               <ArrowDown size={14} />
             </button>
-            <button className="st-chip is-icon" onClick={() => raise(spreadIndex, el.id, 'back')} title={t('journey.studio.toBack')}>
+            <button type="button" className="st-chip is-icon" onClick={() => raise(spreadIndex, el.id, 'back')} title={t('journey.studio.toBack')}>
               <ChevronsDown size={14} />
             </button>
           </div>
diff --git a/client/src/components/Studio/StudioShell.tsx b/client/src/components/Studio/StudioShell.tsx
index 383bb012e..3d5a93e0e 100644
--- a/client/src/components/Studio/StudioShell.tsx
+++ b/client/src/components/Studio/StudioShell.tsx
@@ -46,7 +46,7 @@ export default function StudioShell() {
         <div style={{ fontSize: 13.5, color: 'var(--ink-3)', maxWidth: 320, lineHeight: 1.55 }}>
           {s.t('journey.studio.desktopOnlyHint')}
         </div>
-        <button
+        <button type="button"
           onClick={() => navigate(s.backTo, { replace: true })}
           className="st-tool is-primary"
           style={{ marginTop: 6 }}
@@ -122,7 +122,7 @@ function StudioBar({
 }: { s: Studio; bookView: boolean; setBookView: (v: boolean) => void; onExport: () => void }) {
   return (
     <div className="st-bar">
-      <button onClick={s.close} className="st-back" title={s.t('journey.studio.backToJourney')}>
+      <button type="button" onClick={s.close} className="st-back" title={s.t('journey.studio.backToJourney')}>
         <ArrowLeft size={16} />
         {s.coverUrl
           ? <img src={s.coverUrl} alt="" className="st-cover" />
@@ -154,7 +154,7 @@ function StudioBar({
       />
 
       <div className="st-bar-group">
-        <button
+        <button type="button"
           className={`st-tool ${bookView ? 'is-on' : ''}`}
           onClick={() => setBookView(!bookView)}
           title={s.t('journey.studio.bookView')}
@@ -169,7 +169,7 @@ function StudioBar({
 
         <div className="st-sep" />
 
-        <button
+        <button type="button"
           className="st-tool is-icon"
           disabled={!s.canUndo}
           onClick={s.undo}
@@ -178,7 +178,7 @@ function StudioBar({
         >
           <Undo2 size={15} />
         </button>
-        <button
+        <button type="button"
           className="st-tool is-icon"
           disabled={!s.canRedo}
           onClick={s.redo}
@@ -191,7 +191,7 @@ function StudioBar({
         <div className="st-sep" />
 
         <AutoLayoutButton s={s} />
-        <button
+        <button type="button"
           className="st-tool is-primary"
           onClick={onExport}
           disabled={!s.doc}
@@ -235,7 +235,7 @@ function AutoLayoutButton({ s }: { s: Studio }) {
 
   return (
     <div className="st-picker" ref={box}>
-      <button
+      <button type="button"
         className="st-tool"
         onClick={() => setOpen(o => !o)}
         aria-haspopup="menu"
@@ -249,7 +249,7 @@ function AutoLayoutButton({ s }: { s: Studio }) {
 
       {open && (
         <div className="st-menu" role="menu">
-          <button
+          <button type="button"
             className="st-menu-item"
             role="menuitem"
             disabled={!s.canRelayoutSpread}
@@ -262,7 +262,7 @@ function AutoLayoutButton({ s }: { s: Studio }) {
               </span>
             </span>
           </button>
-          <button
+          <button type="button"
             className="st-menu-item"
             role="menuitem"
             onClick={() => { s.relayoutBook(); setOpen(false) }}
@@ -312,7 +312,7 @@ function FormatPicker({ s }: { s: Studio }) {
 
   return (
     <div className="st-picker" ref={box}>
-      <button
+      <button type="button"
         className="st-tool"
         onClick={() => setOpen(o => !o)}
         aria-haspopup="listbox"
@@ -333,7 +333,7 @@ function FormatPicker({ s }: { s: Studio }) {
             const p = PAGE_PRESETS[id]
             const on = id === s.preset
             return (
-              <button
+              <button type="button"
                 key={id}
                 role="option"
                 aria-selected={on}
@@ -434,14 +434,14 @@ function Workbench({ s, bookView }: { s: Studio; bookView: boolean }) {
       </div>
 
       <div className="st-zoom">
-        <button onClick={() => s.stepZoom(-1)} disabled={!s.canZoomOut} aria-label={s.t('journey.studio.zoomOut')}>
+        <button type="button" onClick={() => s.stepZoom(-1)} disabled={!s.canZoomOut} aria-label={s.t('journey.studio.zoomOut')}>
           <Minus size={15} />
         </button>
         <span className="st-zoom-value">{s.zoomPercent}%</span>
-        <button onClick={() => s.stepZoom(1)} disabled={!s.canZoomIn} aria-label={s.t('journey.studio.zoomIn')}>
+        <button type="button" onClick={() => s.stepZoom(1)} disabled={!s.canZoomIn} aria-label={s.t('journey.studio.zoomIn')}>
           <Plus size={15} />
         </button>
-        <button onClick={s.zoomToFit} aria-label={s.t('journey.studio.zoomFit')} title={s.t('journey.studio.zoomFit')}>
+        <button type="button" onClick={s.zoomToFit} aria-label={s.t('journey.studio.zoomFit')} title={s.t('journey.studio.zoomFit')}>
           <Maximize2 size={14} />
         </button>
         {/*
@@ -453,7 +453,7 @@ function Workbench({ s, bookView }: { s: Studio; bookView: boolean }) {
           photographs, which is the thing worth passing on.
         */}
         <span className="st-zoom-sep" />
-        <button
+        <button type="button"
           onClick={() => s.spread && downloadSpread(s.spread, s.page, s.journey?.title || 'spread')}
           disabled={!s.spread}
           aria-label={s.t('journey.studio.downloadSpread')}
diff --git a/client/src/components/Studio/StudioSidebar.tsx b/client/src/components/Studio/StudioSidebar.tsx
index 84cc1cad0..6f58ebfe6 100644
--- a/client/src/components/Studio/StudioSidebar.tsx
+++ b/client/src/components/Studio/StudioSidebar.tsx
@@ -98,7 +98,7 @@ export function StudioSidebar({
     <>
       <nav className="st-rail" aria-label={t('journey.studio.sections')}>
         {SECTIONS.map(sec => (
-          <button
+          <button type="button"
             key={sec.id}
             className={`st-rail-btn ${section === sec.id ? 'is-on' : ''}`}
             onClick={() => setSection(sec.id)}
@@ -157,7 +157,7 @@ function PagesPanel({
             const editable = canEditSpread(i)
             return (
               <div className="st-thumb-row" key={sp.id}>
-                <button
+                <button type="button"
                   className={`st-thumb ${i === active ? 'is-active' : ''}`}
                   onClick={() => setActive(i)}
                 >
@@ -190,7 +190,7 @@ function PagesPanel({
                 */}
                 {editable && (
                   <div className="st-thumb-actions">
-                    <button
+                    <button type="button"
                       onClick={() => moveSpread(i, -1)}
                       disabled={!canEditSpread(i - 1)}
                       title={t('journey.studio.movePageUp')}
@@ -198,7 +198,7 @@ function PagesPanel({
                     >
                       <ChevronUp size={13} />
                     </button>
-                    <button
+                    <button type="button"
                       onClick={() => moveSpread(i, 1)}
                       disabled={!canEditSpread(i + 1)}
                       title={t('journey.studio.movePageDown')}
@@ -206,14 +206,14 @@ function PagesPanel({
                     >
                       <ChevronDown size={13} />
                     </button>
-                    <button
+                    <button type="button"
                       onClick={() => duplicateSpread(i)}
                       title={t('journey.studio.duplicatePage')}
                       aria-label={t('journey.studio.duplicatePage')}
                     >
                       <Copy size={12} />
                     </button>
-                    <button
+                    <button type="button"
                       className="is-danger"
                       onClick={() => removeSpread(i)}
                       title={t('journey.studio.deletePage')}
@@ -227,7 +227,7 @@ function PagesPanel({
                 {/* Insert between two spreads, where the new one will go — a
                     single "add" at the end cannot express "another page here". */}
                 {editable && (
-                  <button
+                  <button type="button"
                     className="st-thumb-insert"
                     onClick={() => addSpread(i)}
                     title={t('journey.studio.addPageAfter')}
@@ -247,11 +247,11 @@ function PagesPanel({
           not a setting buried in a menu, it is the other half of "add".
         */}
         <div className="st-add-row">
-          <button className="st-add-page" onClick={() => addSpread(lastInner)}>
+          <button type="button" className="st-add-page" onClick={() => addSpread(lastInner)}>
             <Plus size={14} />
             {t('journey.studio.addPage')}
           </button>
-          <button
+          <button type="button"
             className="st-add-page is-import"
             onClick={() => fileInput.current?.click()}
             title={t('journey.studio.importSpreadHint')}
@@ -429,17 +429,17 @@ function ContentPanel({
           spellCheck={false}
         />
         {query && (
-          <button onClick={() => setQuery('')} aria-label={t('common.clear')}>
+          <button type="button" onClick={() => setQuery('')} aria-label={t('common.clear')}>
             <X size={13} />
           </button>
         )}
       </div>
 
       <div className="st-tabs">
-        <button className={tab === 'photos' ? 'is-on' : ''} onClick={() => setTab('photos')}>
+        <button type="button" className={tab === 'photos' ? 'is-on' : ''} onClick={() => setTab('photos')}>
           {t('journey.studio.photos')} <em>{photos.length}</em>
         </button>
-        <button className={tab === 'text' ? 'is-on' : ''} onClick={() => setTab('text')}>
+        <button type="button" className={tab === 'text' ? 'is-on' : ''} onClick={() => setTab('text')}>
           {t('journey.studio.entries')} <em>{entries.length}</em>
         </button>
       </div>
@@ -448,7 +448,7 @@ function ContentPanel({
         {tab === 'photos' ? (
           <div className="st-photo-grid">
             {photos.map(p => (
-              <button
+              <button type="button"
                 key={p.photoId}
                 className="st-photo-cell"
                 onClick={() => dropPhoto(p.photoId)}
@@ -488,17 +488,17 @@ function ContentPanel({
                 )}
                 <div className="st-row" style={{ marginTop: 7 }}>
                   {e.title && (
-                    <button className="st-chip" onClick={() => dropText(e.title!, 22, 700, e.id, 'entry.title')}>
+                    <button type="button" className="st-chip" onClick={() => dropText(e.title!, 22, 700, e.id, 'entry.title')}>
                       {t('journey.studio.addTitle')}
                     </button>
                   )}
                   {e.story && (
-                    <button className="st-chip" onClick={() => dropText(e.story!, 10, 400, e.id, 'entry.story')}>
+                    <button type="button" className="st-chip" onClick={() => dropText(e.story!, 10, 400, e.id, 'entry.story')}>
                       {t('journey.studio.addStory')}
                     </button>
                   )}
                   {e.location && (
-                    <button className="st-chip" onClick={() => dropText(e.location!, 8, 700, e.id, 'entry.location')}>
+                    <button type="button" className="st-chip" onClick={() => dropText(e.location!, 8, 700, e.id, 'entry.location')}>
                       {t('journey.studio.addPlace')}
                     </button>
                   )}
@@ -508,7 +508,7 @@ function ContentPanel({
                     mark placed here and one the auto layout placed read alike.
                   */}
                   {e.date && (
-                    <button
+                    <button type="button"
                       className="st-chip"
                       onClick={() => dropText(
                         formatBookDate(e.date!, locale), 8, 700, e.id, 'entry.date',
@@ -519,7 +519,7 @@ function ContentPanel({
                     </button>
                   )}
                   {e.lat != null && e.lng != null && (
-                    <button
+                    <button type="button"
                       className="st-chip"
                       onClick={() => dropText(
                         formatBookCoords(e.lat!, e.lng!, 'dms'), 8, 700, e.id, 'entry.location',
@@ -535,7 +535,7 @@ function ContentPanel({
                     what you are about to place; "Weather" does not.
                   */}
                   {e.mood && MOOD_CONFIG[e.mood] && (
-                    <button
+                    <button type="button"
                       className="st-chip"
                       onClick={() => dropMark('mood', e.mood!, t(MOOD_CONFIG[e.mood!].label))}
                     >
@@ -543,7 +543,7 @@ function ContentPanel({
                     </button>
                   )}
                   {e.weather && WEATHER_CONFIG[e.weather] && (
-                    <button
+                    <button type="button"
                       className="st-chip"
                       onClick={() => dropMark('weather', e.weather!, t(WEATHER_CONFIG[e.weather!].label))}
                     >
@@ -551,7 +551,7 @@ function ContentPanel({
                     </button>
                   )}
                   {(e.pros.length > 0 || e.cons.length > 0) && (
-                    <button className="st-chip" onClick={() => dropProsCons(e.pros, e.cons)}>
+                    <button type="button" className="st-chip" onClick={() => dropProsCons(e.pros, e.cons)}>
                       {t('journey.studio.addProsCons')}
                       <em>{e.pros.length + e.cons.length}</em>
                     </button>
diff --git a/client/src/components/Studio/StudioSwatches.tsx b/client/src/components/Studio/StudioSwatches.tsx
index d3fbb0ccd..0dd60c0f2 100644
--- a/client/src/components/Studio/StudioSwatches.tsx
+++ b/client/src/components/Studio/StudioSwatches.tsx
@@ -20,7 +20,7 @@ export function Swatches({ value, onPick }: { value: string; onPick: (c: string)
   return (
     <div className="st-swatches">
       {SWATCHES.map(c => (
-        <button
+        <button type="button"
           key={c}
           className={`st-swatch ${value.toLowerCase() === c ? 'is-on' : ''}`}
           style={{ background: c }} // theme-lint-disable — a colour picker shows the colours themselves
diff --git a/client/src/components/Studio/StudioTravelInspector.tsx b/client/src/components/Studio/StudioTravelInspector.tsx
index b848fbc3b..09be1556f 100644
--- a/client/src/components/Studio/StudioTravelInspector.tsx
+++ b/client/src/components/Studio/StudioTravelInspector.tsx
@@ -52,7 +52,7 @@ export function TravelInspector({ el, stats, set, t }: TravelInspectorProps) {
       {stale && (
         <div className="st-section">
           <p className="st-stale">{t('journey.studio.staleHint')}</p>
-          <button
+          <button type="button"
             className="st-chip"
             onClick={() => {
               if (!stats) return
@@ -85,7 +85,7 @@ export function TravelInspector({ el, stats, set, t }: TravelInspectorProps) {
           {BOOK_FONT_ORDER.map(id => {
             const font = BOOK_FONTS[id]
             return (
-              <button
+              <button type="button"
                 key={id}
                 className={`st-font ${el.font === id ? 'is-on' : ''}`}
                 style={{ fontFamily: font.stack }}
@@ -480,7 +480,7 @@ function MapProps({ el, set, t, stats }: Props<BookMapElement> & { stats: Journe
           </Line>
           {hasRoads && roadState !== 'busy' && (
             <div className="st-row" style={{ marginTop: 8 }}>
-              <button className="st-chip" onClick={() => void loadRoads()}>
+              <button type="button" className="st-chip" onClick={() => void loadRoads()}>
                 {t('journey.studio.roadsAgain')}
               </button>
             </div>
diff --git a/client/src/components/Studio/StudioTravelPanel.tsx b/client/src/components/Studio/StudioTravelPanel.tsx
index e3a4c61c2..d0cbf9a64 100644
--- a/client/src/components/Studio/StudioTravelPanel.tsx
+++ b/client/src/components/Studio/StudioTravelPanel.tsx
@@ -68,7 +68,7 @@ function Card({ label, onClick, children, recommended = false, title }: {
   children: React.ReactNode
 }) {
   return (
-    <button
+    <button type="button"
       className={`st-travel-card ${recommended ? 'is-recommended' : ''}`}
       onClick={onClick}
       title={title ? `${label} — ${title}` : label}
diff --git a/client/src/components/Studio/TravelElements.tsx b/client/src/components/Studio/TravelElements.tsx
index 16c3fba33..4684fbb4c 100644
--- a/client/src/components/Studio/TravelElements.tsx
+++ b/client/src/components/Studio/TravelElements.tsx
@@ -100,7 +100,7 @@ const tileOverlapMm = (size: number) => Math.max(0.8, size * 0.04)
 
 /** #rrggbb plus an alpha. */
 function rgba(hex: string, alpha: number): string {
-  const n = parseInt(hex.slice(1), 16)
+  const n = Number.parseInt(hex.slice(1), 16)
   return `rgba(${(n >> 16) & 255}, ${(n >> 8) & 255}, ${n & 255}, ${alpha})`
 }
 
diff --git a/client/src/components/Studio/folioColour.ts b/client/src/components/Studio/folioColour.ts
index 64afe72a1..965bae73a 100644
--- a/client/src/components/Studio/folioColour.ts
+++ b/client/src/components/Studio/folioColour.ts
@@ -49,7 +49,7 @@ export interface FolioInk {
 export function brightness(hex: string): number {
   const clean = hex.replace('#', '')
   const full = clean.length === 3 ? clean.split('').map(c => c + c).join('') : clean
-  const n = parseInt(full.slice(0, 6), 16)
+  const n = Number.parseInt(full.slice(0, 6), 16)
   if (!Number.isFinite(n)) return 1
   const r = (n >> 16) & 255
   const g = (n >> 8) & 255
diff --git a/client/src/components/SystemNotices/ReleaseNoticeModal.tsx b/client/src/components/SystemNotices/ReleaseNoticeModal.tsx
index 98dac19f8..244dd920d 100644
--- a/client/src/components/SystemNotices/ReleaseNoticeModal.tsx
+++ b/client/src/components/SystemNotices/ReleaseNoticeModal.tsx
@@ -130,7 +130,7 @@ export function ReleaseNoticeModal({ notice, visible, onDismiss, onCTA, onSecond
         {/* ── Right: the note ───────────────────────────────────────────── */}
         <div className="rn-note">
           {notice.dismissible && (
-            <button className="rn-close" onClick={onDismiss} aria-label={t('common.close')}>
+            <button type="button" className="rn-close" onClick={onDismiss} aria-label={t('common.close')}>
               <X size={18} strokeWidth={2} />
             </button>
           )}
@@ -161,7 +161,7 @@ export function ReleaseNoticeModal({ notice, visible, onDismiss, onCTA, onSecond
             <div className="rn-support-text">{t(release.supportTextKey)}</div>
             <div className="rn-support-buttons">
               {notice.cta && (
-                <button
+                <button type="button"
                   id={`notice-cta-${notice.id}`}
                   className="rn-support-btn rn-support-bmc"
                   onClick={onCTA}
@@ -171,7 +171,7 @@ export function ReleaseNoticeModal({ notice, visible, onDismiss, onCTA, onSecond
                 </button>
               )}
               {notice.secondaryCta && (
-                <button
+                <button type="button"
                   id={`notice-cta2-${notice.id}`}
                   className="rn-support-btn rn-support-kofi"
                   onClick={onSecondaryCTA}
diff --git a/client/src/components/SystemNotices/SystemNoticeBanner.tsx b/client/src/components/SystemNotices/SystemNoticeBanner.tsx
index 98551f57f..5ef0521b6 100644
--- a/client/src/components/SystemNotices/SystemNoticeBanner.tsx
+++ b/client/src/components/SystemNotices/SystemNoticeBanner.tsx
@@ -82,7 +82,7 @@ function CTALink({
   }
 
   return (
-    <button
+    <button type="button"
       onClick={handleClick}
       className="underline hover:no-underline font-medium ml-3 shrink-0"
     >
@@ -122,7 +122,7 @@ function BannerItem({ notice, onDismiss }: BannerItemProps) {
         )}
       </div>
       {notice.dismissible && (
-        <button
+        <button type="button"
           onClick={onDismiss}
           className="shrink-0 p-2 -mr-2 rounded hover:bg-black/5 dark:hover:bg-white/10 transition"
           aria-label={`Dismiss: ${title}`}
diff --git a/client/src/components/SystemNotices/SystemNoticeModal.tsx b/client/src/components/SystemNotices/SystemNoticeModal.tsx
index 74bd3d98b..ca501e361 100644
--- a/client/src/components/SystemNotices/SystemNoticeModal.tsx
+++ b/client/src/components/SystemNotices/SystemNoticeModal.tsx
@@ -108,7 +108,7 @@ function NoticeContent({ notice, title, body, ctaLabel, secondaryCtaLabel, title
     <div className="flex flex-col relative" style={{ flex: '1 1 0', minHeight: '100%' }}>
       {/* Dismiss X button — only on last page so users read all notices */}
       {notice.dismissible && isLastPage && (
-        <button
+        <button type="button"
           onClick={onDismissAll}
           className="absolute top-4 right-4 z-10 p-2 rounded-lg text-slate-400 hover:text-slate-600 dark:hover:text-slate-300 hover:bg-slate-100 dark:hover:bg-slate-800 transition-colors"
           aria-label="Dismiss"
@@ -257,7 +257,7 @@ function NoticeContent({ notice, title, body, ctaLabel, secondaryCtaLabel, title
         {total > 1 && (
           <div className="flex flex-col items-center gap-1">
             <div className="flex items-center gap-2">
-              <button
+              <button type="button"
                 onClick={onPrev}
                 disabled={!canPage || currentPage === 0}
                 aria-label={t('system_notice.pager.prev')}
@@ -267,7 +267,7 @@ function NoticeContent({ notice, title, body, ctaLabel, secondaryCtaLabel, title
               </button>
 
               {Array.from({ length: total }, (_, i) => (
-                <button
+                <button type="button"
                   key={i}
                   onClick={() => { if (canPage) onGoto(i); }}
                   aria-label={t('system_notice.pager.goto').replace('{n}', String(i + 1))}
@@ -281,7 +281,7 @@ function NoticeContent({ notice, title, body, ctaLabel, secondaryCtaLabel, title
                 />
               ))}
 
-              <button
+              <button type="button"
                 onClick={onNext}
                 disabled={!canPage || currentPage === total - 1}
                 aria-label={t('system_notice.pager.next')}
@@ -303,7 +303,7 @@ function NoticeContent({ notice, title, body, ctaLabel, secondaryCtaLabel, title
         <div className="flex flex-col items-center gap-3">
           {ctaLabel && isLastPage ? (
             <div className="flex w-full flex-col sm:flex-row gap-2.5">
-              <button
+              <button type="button"
                 id={`notice-cta-${notice.id}`}
                 onClick={onCTA}
                 className={`flex-1 h-11 inline-flex items-center justify-center gap-2 rounded-lg font-semibold shadow-sm transition active:scale-[0.98] ${
@@ -316,7 +316,7 @@ function NoticeContent({ notice, title, body, ctaLabel, secondaryCtaLabel, title
                 {ctaLabel}
               </button>
               {secondaryCtaLabel && (
-                <button
+                <button type="button"
                   id={`notice-cta2-${notice.id}`}
                   onClick={onSecondaryCTA}
                   className={`flex-1 h-11 inline-flex items-center justify-center gap-2 rounded-lg font-semibold shadow-sm transition active:scale-[0.98] ${
@@ -331,7 +331,7 @@ function NoticeContent({ notice, title, body, ctaLabel, secondaryCtaLabel, title
               )}
             </div>
           ) : (notice.dismissible || isLastPage) && (
-            <button
+            <button type="button"
               id={`notice-cta-${notice.id}`}
               onClick={isLastPage ? onDismissAll : onNext}
               className="w-full h-11 rounded-lg bg-blue-600 hover:bg-blue-700 text-white font-medium transition-colors"
diff --git a/client/src/components/Todo/TodoListPanel.tsx b/client/src/components/Todo/TodoListPanel.tsx
index 4c8254210..f02a8f54e 100644
--- a/client/src/components/Todo/TodoListPanel.tsx
+++ b/client/src/components/Todo/TodoListPanel.tsx
@@ -36,7 +36,7 @@ function SidebarItem({ id, icon: Icon, label, count, color, active, compact, onS
   onSelect: (id: string) => void
 }) {
   return (
-    <button onClick={() => onSelect(id)}
+    <button type="button" onClick={() => onSelect(id)}
       title={compact ? label : undefined}
       style={{
         display: 'flex', alignItems: 'center', justifyContent: compact ? 'center' : 'flex-start',
@@ -162,7 +162,7 @@ export default function TodoListPanel({ tripId, items, addItemSignal = 0 }: { tr
         {!isMobile && <div style={{ fontSize: 'calc(10px * var(--fs-scale-caption, 1))', fontWeight: 600, color: 'var(--text-faint)', padding: '16px 12px 4px', textTransform: 'uppercase', letterSpacing: '0.05em' }}>
           {t('todo.sidebar.sortBy')}
         </div>}
-        <button onClick={() => setSortByPrio(v => !v)}
+        <button type="button" onClick={() => setSortByPrio(v => !v)}
           title={isMobile ? t('todo.priority') : undefined}
           style={{
             display: 'flex', alignItems: 'center', justifyContent: isMobile ? 'center' : 'flex-start',
@@ -194,10 +194,10 @@ export default function TodoListPanel({ tripId, items, addItemSignal = 0 }: { tr
                 onKeyDown={e => { if (e.key === 'Enter') addCategory(); if (e.key === 'Escape') { setAddingCategory(false); setNewCategoryName('') } }}
                 placeholder={t('todo.newCategory')}
                 style={{ flex: 1, fontSize: 'calc(12px * var(--fs-scale-body, 1))', padding: '4px 6px', border: '1px solid var(--border-primary)', borderRadius: 5, background: 'var(--bg-hover)', color: 'var(--text-primary)', fontFamily: 'inherit', minWidth: 0 }} />
-              <button onClick={addCategory} style={{ background: 'none', border: 'none', cursor: 'pointer', color: '#22c55e', padding: 2 }}><Check size={13} /></button>
+              <button type="button" onClick={addCategory} style={{ background: 'none', border: 'none', cursor: 'pointer', color: '#22c55e', padding: 2 }}><Check size={13} /></button>
             </div>
           ) : (
-            <button onClick={() => setAddingCategory(true)}
+            <button type="button" onClick={() => setAddingCategory(true)}
               title={isMobile ? t('todo.addCategory') : undefined}
               style={{ display: 'flex', alignItems: 'center', justifyContent: isMobile ? 'center' : 'flex-start', gap: isMobile ? 0 : 6, padding: isMobile ? '8px 0' : '7px 12px', fontSize: 'calc(12px * var(--fs-scale-body, 1))', color: 'var(--text-faint)', background: 'none', border: 'none', cursor: 'pointer', fontFamily: 'inherit', width: '100%', textAlign: 'left' }}>
               <Plus size={isMobile ? 18 : 13} /> {!isMobile && t('todo.addCategory')}
@@ -391,7 +391,7 @@ function DetailPane({ item, tripId, categories, members, onClose }: {
       {/* Header */}
       <div style={{ display: 'flex', alignItems: 'center', justifyContent: 'space-between', padding: '16px 20px 12px', borderBottom: '1px solid var(--border-faint)' }}>
         <span style={{ fontSize: 'calc(14px * var(--fs-scale-body, 1))', fontWeight: 700, color: 'var(--text-primary)' }}>{t('todo.detail.title')}</span>
-        <button onClick={onClose} style={{ background: 'none', border: 'none', cursor: 'pointer', color: 'var(--text-faint)', padding: 4 }}>
+        <button type="button" onClick={onClose} style={{ background: 'none', border: 'none', cursor: 'pointer', color: 'var(--text-faint)', padding: 4 }}>
           <X size={16} />
         </button>
       </div>
@@ -421,7 +421,7 @@ function DetailPane({ item, tripId, categories, members, onClose }: {
               const cfg = PRIO_CONFIG[p]
               const isActive = priority === p
               return (
-                <button key={p} onClick={() => canEdit && setPriority(p)}
+                <button type="button" key={p} onClick={() => canEdit && setPriority(p)}
                   style={{
                     flex: 1, padding: '6px 0', borderRadius: 6, fontSize: 'calc(11px * var(--fs-scale-caption, 1))', fontWeight: 600, cursor: canEdit ? 'pointer' : 'default',
                     fontFamily: 'inherit', display: 'flex', alignItems: 'center', justifyContent: 'center', gap: 4,
@@ -527,7 +527,7 @@ function DetailPane({ item, tripId, categories, members, onClose }: {
       {/* Footer actions */}
       {canEdit && (
         <div style={{ padding: '12px 20px', borderTop: '1px solid var(--border-faint)', display: 'flex', gap: 8 }}>
-          <button onClick={handleDelete}
+          <button type="button" onClick={handleDelete}
             style={{
               flex: 1, padding: '9px 16px', borderRadius: 8, fontSize: 'calc(12px * var(--fs-scale-body, 1))', fontWeight: 600, cursor: 'pointer', fontFamily: 'inherit',
               border: '1px solid var(--border-primary)', background: 'transparent', color: 'var(--text-secondary)',
@@ -536,7 +536,7 @@ function DetailPane({ item, tripId, categories, members, onClose }: {
             <Trash2 size={13} />
             {t('todo.detail.delete')}
           </button>
-          <button onClick={save} disabled={!hasChanges || saving}
+          <button type="button" onClick={save} disabled={!hasChanges || saving}
             style={{
               flex: 1, padding: '9px 16px', borderRadius: 8, fontSize: 'calc(12px * var(--fs-scale-body, 1))', fontWeight: 600, cursor: hasChanges ? 'pointer' : 'default', fontFamily: 'inherit',
               border: 'none', background: hasChanges ? 'var(--text-primary)' : 'var(--border-faint)',
@@ -594,7 +594,7 @@ function NewTaskPane({ tripId, categories, members, defaultCategory, onCreated,
     }}>
       <div style={{ display: 'flex', alignItems: 'center', justifyContent: 'space-between', padding: '16px 20px 12px', borderBottom: '1px solid var(--border-faint)' }}>
         <span style={{ fontSize: 'calc(14px * var(--fs-scale-body, 1))', fontWeight: 700, color: 'var(--text-primary)' }}>{t('todo.newItem')}</span>
-        <button onClick={onClose} style={{ background: 'none', border: 'none', cursor: 'pointer', color: 'var(--text-faint)', padding: 4 }}>
+        <button type="button" onClick={onClose} style={{ background: 'none', border: 'none', cursor: 'pointer', color: 'var(--text-faint)', padding: 4 }}>
           <X size={16} />
         </button>
       </div>
@@ -668,7 +668,7 @@ function NewTaskPane({ tripId, categories, members, defaultCategory, onCreated,
               const cfg = PRIO_CONFIG[p]
               const isActive = priority === p
               return (
-                <button key={p} onClick={() => setPriority(p)}
+                <button type="button" key={p} onClick={() => setPriority(p)}
                   style={{
                     flex: 1, padding: '6px 0', borderRadius: 6, fontSize: 'calc(11px * var(--fs-scale-caption, 1))', fontWeight: 600, cursor: 'pointer',
                     fontFamily: 'inherit', display: 'flex', alignItems: 'center', justifyContent: 'center', gap: 4,
@@ -714,7 +714,7 @@ function NewTaskPane({ tripId, categories, members, defaultCategory, onCreated,
       </div>
 
       <div style={{ padding: '12px 20px', borderTop: '1px solid var(--border-faint)' }}>
-        <button onClick={create} disabled={!name.trim() || saving}
+        <button type="button" onClick={create} disabled={!name.trim() || saving}
           style={{
             width: '100%', padding: '9px 16px', borderRadius: 8, fontSize: 'calc(12px * var(--fs-scale-body, 1))', fontWeight: 600, cursor: name.trim() ? 'pointer' : 'default', fontFamily: 'inherit',
             border: 'none', background: name.trim() ? 'var(--text-primary)' : 'var(--border-faint)',
diff --git a/client/src/components/Todo/TodoRow.tsx b/client/src/components/Todo/TodoRow.tsx
index f49941b9d..1e8907b2a 100644
--- a/client/src/components/Todo/TodoRow.tsx
+++ b/client/src/components/Todo/TodoRow.tsx
@@ -61,7 +61,7 @@ export default function TodoRow({ item, members, categories, today, isSelected,
       )}
 
       {/* Checkbox */}
-      <button onClick={e => { e.stopPropagation(); if (canEdit) onToggle(item.id, !done) }}
+      <button type="button" onClick={e => { e.stopPropagation(); if (canEdit) onToggle(item.id, !done) }}
         style={{ background: 'none', border: 'none', cursor: canEdit ? 'pointer' : 'default', padding: 0, flexShrink: 0,
           color: done ? '#22c55e' : 'var(--border-primary)' }}>
         {done ? <CheckSquare size={18} /> : <Square size={18} />}
diff --git a/client/src/components/Todo/useTodoList.ts b/client/src/components/Todo/useTodoList.ts
index 79bd22739..fea2b5392 100644
--- a/client/src/components/Todo/useTodoList.ts
+++ b/client/src/components/Todo/useTodoList.ts
@@ -63,7 +63,10 @@ export function useTodoList(tripId: number, items: TodoItem[], addItemSignal: nu
   const categories = useMemo(() => {
     const cats = new Set<string>()
     items.forEach(i => { if (i.category) cats.add(i.category) })
-    return Array.from(cats).sort()
+    // Category names are free text the user types, and TREK ships 23 locales — a
+    // bare .sort() is byte order, which files every accented name behind the whole
+    // ASCII range ("Übernachtung" after "Zelt").
+    return Array.from(cats).sort((a, b) => a.localeCompare(b))
   }, [items])
 
   // due_date is a bare calendar date, so "today" has to be the user's calendar
diff --git a/client/src/components/Trips/TripFormModal.tsx b/client/src/components/Trips/TripFormModal.tsx
index e253fda38..0d000d23e 100644
--- a/client/src/components/Trips/TripFormModal.tsx
+++ b/client/src/components/Trips/TripFormModal.tsx
@@ -396,7 +396,7 @@ export default function TripFormModal({ isOpen, onClose, onSave, trip, onCoverUp
               <button type="button" onClick={onClose} className={ghostBtnCls}>
                 {t('common.cancel')}
               </button>
-              <button onClick={handleSubmit} disabled={isLoading} className={primaryBtnCls}>
+              <button type="button" onClick={handleSubmit} disabled={isLoading} className={primaryBtnCls}>
                 {isLoading
                   ? <><div className="w-4 h-4 border-2 border-accent-text/30 border-t-accent-text rounded-full animate-spin" />{t('common.saving')}</>
                   : isEditing ? t('common.update') : t('dashboard.createTrip')}
diff --git a/client/src/components/Trips/TripMembersModal.tsx b/client/src/components/Trips/TripMembersModal.tsx
index 787e9ad36..85c570a4d 100644
--- a/client/src/components/Trips/TripMembersModal.tsx
+++ b/client/src/components/Trips/TripMembersModal.tsx
@@ -106,7 +106,7 @@ function ShareLinkSection({ tripId, t }: { tripId: number; t: (key: string, para
           { key: 'share_budget', label: t('share.permBudget') },
           { key: 'share_collab', label: t('share.permCollab') },
         ].map(opt => (
-          <button key={opt.key} onClick={() => !opt.always && handleUpdatePerms(opt.key, !perms[opt.key])}
+          <button type="button" key={opt.key} onClick={() => !opt.always && handleUpdatePerms(opt.key, !perms[opt.key])}
             style={{
               display: 'flex', alignItems: 'center', gap: 5, padding: '4px 10px', borderRadius: 20,
               border: '1.5px solid', fontSize: 'calc(11px * var(--fs-scale-caption, 1))', fontWeight: 500, cursor: opt.always ? 'default' : 'pointer',
@@ -132,7 +132,7 @@ function ShareLinkSection({ tripId, t }: { tripId: number; t: (key: string, para
               flex: 1, border: 'none', background: 'none', fontSize: 'calc(11px * var(--fs-scale-caption, 1))',
               outline: 'none', fontFamily: 'monospace',
             }} />
-            <button onClick={handleCopy} style={{
+            <button type="button" onClick={handleCopy} style={{
               display: 'flex', alignItems: 'center', gap: 4, padding: '4px 8px', borderRadius: 6,
               border: 'none', background: copied ? '#16a34a' : 'var(--accent)', color: copied ? 'white' : 'var(--accent-text)',
               fontSize: 'calc(10px * var(--fs-scale-caption, 1))', fontWeight: 600, cursor: 'pointer', fontFamily: 'inherit', transition: 'background 0.2s',
@@ -140,7 +140,7 @@ function ShareLinkSection({ tripId, t }: { tripId: number; t: (key: string, para
               {copied ? <><Check size={10} /> {t('common.copied')}</> : <><Copy size={10} /> {t('common.copy')}</>}
             </button>
           </div>
-          <button onClick={handleDelete} style={{
+          <button type="button" onClick={handleDelete} style={{
             display: 'flex', alignItems: 'center', justifyContent: 'center', gap: 5,
             padding: '6px 0', borderRadius: 8, border: '1px solid rgba(239,68,68,0.3)',
             background: 'rgba(239,68,68,0.06)', color: '#ef4444', fontSize: 'calc(11px * var(--fs-scale-caption, 1))', fontWeight: 500,
@@ -150,7 +150,7 @@ function ShareLinkSection({ tripId, t }: { tripId: number; t: (key: string, para
           </button>
         </div>
       ) : (
-        <button onClick={handleCreate} className="border border-dashed border-edge text-content-muted" style={{
+        <button type="button" onClick={handleCreate} className="border border-dashed border-edge text-content-muted" style={{
           display: 'flex', alignItems: 'center', justifyContent: 'center', gap: 6,
           width: '100%', padding: '8px 0', borderRadius: 8,
           background: 'none', fontSize: 'calc(12px * var(--fs-scale-body, 1))', fontWeight: 500,
@@ -222,7 +222,7 @@ function TripInviteLinkSection({ tripId, t }: { tripId: number; t: (key: string,
         <div style={{ display: 'flex', flexDirection: 'column', gap: 8 }}>
           <div className="bg-surface-tertiary border border-edge-faint" style={{ display: 'flex', alignItems: 'center', gap: 6, padding: '8px 10px', borderRadius: 8 }}>
             <input type="text" value={inviteUrl} readOnly className="text-content" style={{ flex: 1, border: 'none', background: 'none', fontSize: 'calc(11px * var(--fs-scale-caption, 1))', outline: 'none', fontFamily: 'monospace' }} />
-            <button onClick={copy} style={{
+            <button type="button" onClick={copy} style={{
               display: 'flex', alignItems: 'center', gap: 4, padding: '4px 8px', borderRadius: 6,
               border: 'none', background: copied ? '#16a34a' : 'var(--accent)', color: copied ? 'white' : 'var(--accent-text)',
               fontSize: 'calc(10px * var(--fs-scale-caption, 1))', fontWeight: 600, cursor: 'pointer', fontFamily: 'inherit', transition: 'background 0.2s',
@@ -231,14 +231,14 @@ function TripInviteLinkSection({ tripId, t }: { tripId: number; t: (key: string,
             </button>
           </div>
           <div style={{ display: 'flex', gap: 8 }}>
-            <button onClick={create} disabled={busy} className="border border-edge text-content-muted" style={{
+            <button type="button" onClick={create} disabled={busy} className="border border-edge text-content-muted" style={{
               flex: 1, display: 'flex', alignItems: 'center', justifyContent: 'center', gap: 5,
               padding: '6px 0', borderRadius: 8, background: 'none', fontSize: 'calc(11px * var(--fs-scale-caption, 1))', fontWeight: 500,
               cursor: busy ? 'default' : 'pointer', fontFamily: 'inherit',
             }}>
               <Link2 size={11} /> {t('trip.invite.regenerate')}
             </button>
-            <button onClick={remove} disabled={busy} style={{
+            <button type="button" onClick={remove} disabled={busy} style={{
               flex: 1, display: 'flex', alignItems: 'center', justifyContent: 'center', gap: 5,
               padding: '6px 0', borderRadius: 8, border: '1px solid rgba(239,68,68,0.3)',
               background: 'rgba(239,68,68,0.06)', color: '#ef4444', fontSize: 'calc(11px * var(--fs-scale-caption, 1))', fontWeight: 500,
@@ -249,7 +249,7 @@ function TripInviteLinkSection({ tripId, t }: { tripId: number; t: (key: string,
           </div>
         </div>
       ) : (
-        <button onClick={create} disabled={busy} className="border border-dashed border-edge text-content-muted" style={{
+        <button type="button" onClick={create} disabled={busy} className="border border-dashed border-edge text-content-muted" style={{
           display: 'flex', alignItems: 'center', justifyContent: 'center', gap: 6,
           width: '100%', padding: '8px 0', borderRadius: 8,
           background: 'none', fontSize: 'calc(12px * var(--fs-scale-body, 1))', fontWeight: 500,
@@ -470,7 +470,7 @@ export default function TripMembersModal({ isOpen, onClose, tripId, tripTitle, o
               style={{ flex: 1 }}
               size="sm"
             />
-            <button
+            <button type="button"
               onClick={handleAdd}
               disabled={adding || !selectedUserId}
               style={{
@@ -526,7 +526,7 @@ export default function TripMembersModal({ isOpen, onClose, tripId, tripTitle, o
                       </div>
                     </div>
                     {isCurrentOwner && member.role !== 'owner' && (
-                      <button
+                      <button type="button"
                         onClick={() => handleTransfer(member.id, member.username)}
                         disabled={transferringId === member.id}
                         title={t('members.makeOwner')}
@@ -538,7 +538,7 @@ export default function TripMembersModal({ isOpen, onClose, tripId, tripTitle, o
                       </button>
                     )}
                     {canRemove && (
-                      <button
+                      <button type="button"
                         onClick={() => handleRemove(member.id, isSelf)}
                         disabled={removingId === member.id}
                         title={isSelf ? t('members.leaveTrip') : t('members.removeAccess')}
@@ -594,7 +594,7 @@ export default function TripMembersModal({ isOpen, onClose, tripId, tripTitle, o
                 )}
                 {isCurrentOwner && renamingGuestId !== g.id && (
                   <>
-                    <button
+                    <button type="button"
                       onClick={() => { renameCommittedRef.current = false; setRenamingGuestId(g.id); setRenameValue(g.username) }}
                       title={t('common.rename')}
                       style={{ background: 'none', border: 'none', cursor: 'pointer', padding: '4px', borderRadius: 6, display: 'flex', color: 'var(--text-faint)' }}
@@ -603,7 +603,7 @@ export default function TripMembersModal({ isOpen, onClose, tripId, tripTitle, o
                     >
                       <Pencil size={13} />
                     </button>
-                    <button
+                    <button type="button"
                       onClick={() => handleDeleteGuest(g.id)}
                       disabled={removingId === g.id}
                       title={t('members.removeAccess')}
@@ -630,7 +630,7 @@ export default function TripMembersModal({ isOpen, onClose, tripId, tripTitle, o
                 className="bg-surface border border-edge text-content"
                 style={{ flex: 1, minWidth: 0, fontSize: 'calc(13px * var(--fs-scale-body, 1))', padding: '8px 10px', borderRadius: 10, outline: 'none', fontFamily: 'inherit' }}
               />
-              <button
+              <button type="button"
                 onClick={handleAddGuest}
                 disabled={addingGuest || !newGuestName.trim()}
                 style={{
diff --git a/client/src/components/Vacay/VacayCalendar.tsx b/client/src/components/Vacay/VacayCalendar.tsx
index 7707115c4..08a844236 100644
--- a/client/src/components/Vacay/VacayCalendar.tsx
+++ b/client/src/components/Vacay/VacayCalendar.tsx
@@ -218,7 +218,7 @@ export default function VacayCalendar() {
       {/* Floating toolbar — lift above the mobile bottom nav (z-60). On desktop --bottom-nav-h is 0px. */}
       <div className="sticky mt-3 sm:mt-4 flex items-center justify-center px-2" style={{ bottom: 'calc(var(--bottom-nav-h, 0px) + 12px)', zIndex: 61 }}>
         <div className="vg-card flex items-center gap-1.5 sm:gap-2 px-2 sm:px-3 py-1.5 sm:py-2 rounded-full">
-          <button
+          <button type="button"
             onClick={() => setMode('vacation')}
             className="flex items-center gap-1 sm:gap-1.5 px-2 sm:px-3 py-1.5 rounded-full text-[11px] sm:text-xs font-semibold transition-[background-color,color] duration-150 ease-[cubic-bezier(0.23,1,0.32,1)]"
             style={mode === 'vacation'
@@ -229,7 +229,7 @@ export default function VacayCalendar() {
             {selectedUser ? selectedUser.username : t('vacay.modeVacation')}
           </button>
           {companyHolidaysEnabled && (
-            <button
+            <button type="button"
               onClick={() => setMode('company')}
               className="flex items-center gap-1 sm:gap-1.5 px-2 sm:px-3 py-1.5 rounded-full text-[11px] sm:text-xs font-semibold transition-[background-color,color] duration-150 ease-[cubic-bezier(0.23,1,0.32,1)]"
               style={companyMode
@@ -243,7 +243,7 @@ export default function VacayCalendar() {
           {/* Divider — comp/flex and half-day are modifiers, not modes. */}
           <span className="w-px self-stretch my-0.5" style={{ background: 'var(--vg-line)' }} aria-hidden />
 
-          <button
+          <button type="button"
             onClick={() => setCompDay(v => !v)}
             title={t('vacay.modeCompHint')}
             aria-pressed={compDay}
@@ -262,7 +262,7 @@ export default function VacayCalendar() {
             {t('vacay.modeComp')}
           </button>
 
-          <button
+          <button type="button"
             onClick={() => setHalfDay(v => !v)}
             title={t('vacay.modeHalfHint')}
             aria-pressed={halfDay}
diff --git a/client/src/components/Vacay/VacayPersons.tsx b/client/src/components/Vacay/VacayPersons.tsx
index 43bb30e48..86bb4788d 100644
--- a/client/src/components/Vacay/VacayPersons.tsx
+++ b/client/src/components/Vacay/VacayPersons.tsx
@@ -67,7 +67,7 @@ export default function VacayPersons() {
     <div className="vg-card rounded-[22px]" style={{ padding: '14px 18px' }}>
       <div className="flex items-center justify-between mb-2">
         <span style={{ fontSize: 11, fontWeight: 600, textTransform: 'uppercase', letterSpacing: '0.14em', color: 'var(--vg-ink3)' }}>{t('vacay.persons')}</span>
-        <button onClick={() => { setShowInvite(true); loadAvailable() }}
+        <button type="button" onClick={() => { setShowInvite(true); loadAvailable() }}
           className="w-7 h-7 rounded-lg flex items-center justify-center transition-colors"
           style={{ color: 'var(--vg-ink3)' }}>
           <UserPlus size={15} />
@@ -88,7 +88,7 @@ export default function VacayPersons() {
                 background: isSelected ? 'var(--vg-surf2)' : 'transparent',
                 border: `1px solid ${isSelected ? 'var(--vg-line)' : 'transparent'}`,
               }}>
-              <button
+              <button type="button"
                 onClick={(e) => { e.stopPropagation(); setColorEditUserId(u.id); setShowColorPicker(true) }}
                 className="w-3 h-3 rounded-full shrink-0 transition-transform hover:scale-125"
                 style={{ backgroundColor: u.color, cursor: 'pointer' }}
@@ -114,7 +114,7 @@ export default function VacayPersons() {
               {inv.username}
             </span>
             <VacayBadge label={t('vacay.pending')} tone="amber" />
-            <button onClick={() => cancelInvite(inv.user_id)}
+            <button type="button" onClick={() => cancelInvite(inv.user_id)}
               className="ml-auto opacity-0 group-hover:opacity-100 text-[10px] px-1.5 py-0.5 rounded transition-all"
               style={{ color: 'var(--vg-ink3)' }}>
               {t('common.cancel')}
@@ -131,7 +131,7 @@ export default function VacayPersons() {
             onClick={e => e.stopPropagation()}>
             <div className="flex items-center justify-between p-5 border-b border-edge-secondary">
               <h2 className="text-base font-semibold text-content">{t('vacay.inviteUser')}</h2>
-              <button onClick={() => setShowInvite(false)} className="p-1.5 rounded-lg transition-colors text-content-faint">
+              <button type="button" onClick={() => setShowInvite(false)} className="p-1.5 rounded-lg transition-colors text-content-faint">
                 <X size={16} />
               </button>
             </div>
@@ -149,10 +149,10 @@ export default function VacayPersons() {
                 />
               )}
               <div className="flex gap-3 justify-end pt-2">
-                <button onClick={() => setShowInvite(false)} className="px-4 py-2 text-sm rounded-lg text-content-muted border border-edge">
+                <button type="button" onClick={() => setShowInvite(false)} className="px-4 py-2 text-sm rounded-lg text-content-muted border border-edge">
                   {t('common.cancel')}
                 </button>
-                <button onClick={handleInvite} disabled={!selectedInviteUser || inviting}
+                <button type="button" onClick={handleInvite} disabled={!selectedInviteUser || inviting}
                   className="px-4 py-2 text-sm rounded-lg transition-colors flex items-center gap-1.5 disabled:opacity-40 bg-content text-surface-card">
                   {inviting && <Loader2 size={13} className="animate-spin" />}
                   {t('vacay.sendInvite')}
@@ -172,14 +172,14 @@ export default function VacayPersons() {
             onClick={e => e.stopPropagation()}>
             <div className="flex items-center justify-between p-5 border-b border-edge-secondary">
               <h2 className="text-base font-semibold text-content">{t('vacay.changeColor')}</h2>
-              <button onClick={() => { setShowColorPicker(false); setColorEditUserId(null) }} className="p-1.5 rounded-lg transition-colors text-content-faint">
+              <button type="button" onClick={() => { setShowColorPicker(false); setColorEditUserId(null) }} className="p-1.5 rounded-lg transition-colors text-content-faint">
                 <X size={16} />
               </button>
             </div>
             <div className="p-5">
               <div className="flex flex-wrap gap-2 justify-center">
                 {PRESET_COLORS.map(c => (
-                  <button key={c} onClick={() => handleColorChange(c)}
+                  <button type="button" key={c} onClick={() => handleColorChange(c)}
                     className={`w-8 h-8 rounded-full transition-transform duration-150 ease-[cubic-bezier(0.23,1,0.32,1)] ${editingUserColor === c ? 'ring-2 ring-offset-2 scale-110' : 'hover:scale-110'}`}
                     style={{ backgroundColor: c }} />
                 ))}
diff --git a/client/src/components/Vacay/VacaySettings.tsx b/client/src/components/Vacay/VacaySettings.tsx
index caba93a19..fd59f5176 100644
--- a/client/src/components/Vacay/VacaySettings.tsx
+++ b/client/src/components/Vacay/VacaySettings.tsx
@@ -76,7 +76,7 @@ export default function VacaySettings({ onClose }: VacaySettingsProps) {
               const current: number[] = plan.weekend_days ? String(plan.weekend_days).split(',').map(Number) : [0, 6]
               const active = current.includes(day)
               return (
-                <button key={day} onClick={() => {
+                <button type="button" key={day} onClick={() => {
                   const next = active ? current.filter(d => d !== day) : [...current, day]
                   updatePlan({ weekend_days: next.join(',') })
                 }}
@@ -111,7 +111,7 @@ export default function VacaySettings({ onClose }: VacaySettingsProps) {
           ].map(({ value, label }) => {
             const active = (plan.week_start ?? 1) === value
             return (
-              <button key={value} onClick={() => updatePlan({ week_start: value })}
+              <button type="button" key={value} onClick={() => updatePlan({ week_start: value })}
                 style={{
                   padding: '4px 10px', borderRadius: 8, fontSize: 'calc(12px * var(--fs-scale-body, 1))', fontWeight: 600, cursor: 'pointer',
                   fontFamily: 'inherit', border: '1px solid', transition: 'all 0.12s',
@@ -194,7 +194,7 @@ export default function VacaySettings({ onClose }: VacaySettingsProps) {
                 onCancel={() => setShowAddForm(false)}
               />
             ) : (
-              <button
+              <button type="button"
                 onClick={() => setShowAddForm(true)}
                 className="w-full flex items-center justify-center gap-1.5 text-xs font-medium py-2.5 rounded-xl border border-dashed transition-colors"
                 style={{ borderColor: 'var(--vg-line2)', background: 'var(--vg-surf)', color: 'var(--vg-ink2)' }}
@@ -242,7 +242,7 @@ export default function VacaySettings({ onClose }: VacaySettingsProps) {
                 onCancel={() => setShowAddSchoolForm(false)}
               />
             ) : (
-              <button
+              <button type="button"
                 onClick={() => setShowAddSchoolForm(true)}
                 className="flex items-center gap-1.5 text-xs px-2 py-1.5 rounded-md transition-colors text-content-muted bg-surface-secondary"
               >
@@ -278,7 +278,7 @@ export default function VacaySettings({ onClose }: VacaySettingsProps) {
               ))}
             </div>
             <div className="px-4 py-3 border-t border-t-[rgba(239,68,68,0.1)]">
-              <button
+              <button type="button"
                 onClick={async () => {
                   await dissolve()
                   toast.success(t('vacay.dissolved'))
@@ -363,7 +363,7 @@ function YearTypePicker() {
           <div className="flex-1 min-w-0">
             <CustomSelect
               value={String(yearSettings.year_start_month)}
-              onChange={v => save({ year_start_month: parseInt(String(v), 10) })}
+              onChange={v => save({ year_start_month: Number.parseInt(String(v), 10) })}
               options={monthNames.map((label, i) => ({ value: String(i + 1), label }))}
               placeholder={t('vacay.yearStartMonth')}
             />
@@ -371,7 +371,7 @@ function YearTypePicker() {
           <div className="w-[92px] shrink-0">
             <CustomSelect
               value={String(yearSettings.year_start_day)}
-              onChange={v => save({ year_start_day: parseInt(String(v), 10) })}
+              onChange={v => save({ year_start_day: Number.parseInt(String(v), 10) })}
               options={Array.from({ length: maxDay }, (_, i) => ({ value: String(i + 1), label: String(i + 1) }))}
               placeholder={t('vacay.yearStartDay')}
             />
@@ -425,7 +425,7 @@ function SettingToggle({ icon: Icon, label, hint, value, onChange }: SettingTogg
           <p className="text-[11px] text-content-faint">{hint}</p>
         </div>
       </div>
-      <button onClick={onChange}
+      <button type="button" onClick={onChange}
         className={`relative shrink-0 inline-flex h-6 w-11 items-center rounded-full transition-colors ${value ? 'bg-content' : 'bg-edge'}`}>
         <span className="absolute left-1 h-4 w-4 rounded-full transition-transform duration-200 bg-surface-card"
           style={{ transform: value ? 'translateX(20px)' : 'translateX(0)' }} />
@@ -485,7 +485,7 @@ function CalendarRow({ cal, countries, calendarType, onUpdate, onDelete }: {
   return (
     <div className="flex gap-3 items-start p-3 rounded-xl" style={{ background: 'var(--vg-surf)', border: '1px solid var(--vg-line)' }}>
       <div style={{ position: 'relative', flexShrink: 0 }}>
-        <button
+        <button type="button"
           onClick={() => setShowColorPicker(!showColorPicker)}
           style={{ width: 28, height: 28, borderRadius: 8, background: localColor, border: '2px solid var(--border-primary)', cursor: 'pointer' }}
           title={t('vacay.calendarColor')}
@@ -493,7 +493,7 @@ function CalendarRow({ cal, countries, calendarType, onUpdate, onDelete }: {
         {showColorPicker && (
           <div style={{ position: 'absolute', top: 34, left: 0, zIndex: 50, background: 'var(--bg-card)', border: '1px solid var(--border-primary)', borderRadius: 12, padding: 8, boxShadow: '0 8px 24px rgba(0,0,0,0.12)', display: 'grid', gridTemplateColumns: 'repeat(4, 1fr)', gap: 4, width: 120 }}>
             {PRESET_COLORS.map(c => (
-              <button key={c} onClick={() => { setLocalColor(c); setShowColorPicker(false); if (c !== cal.color) onUpdate({ color: c }) }}
+              <button type="button" key={c} onClick={() => { setLocalColor(c); setShowColorPicker(false); if (c !== cal.color) onUpdate({ color: c }) }}
                 style={{ width: 24, height: 24, borderRadius: 6, background: c, border: localColor === c ? '2px solid var(--text-primary)' : '2px solid transparent', cursor: 'pointer' }} />
             ))}
           </div>
@@ -526,7 +526,7 @@ function CalendarRow({ cal, countries, calendarType, onUpdate, onDelete }: {
           />
         )}
       </div>
-      <button
+      <button type="button"
         onClick={onDelete}
         className="shrink-0 p-1.5 rounded-md transition-colors text-content-faint"
         onMouseEnter={e => { (e.currentTarget as HTMLButtonElement).style.background = 'rgba(239,68,68,0.1)' }}
@@ -568,7 +568,7 @@ function AddCalendarForm({ countries, calendarType, onAdd, onCancel, defaultColo
   return (
     <div className="flex gap-3 items-start p-3 rounded-xl border border-dashed" style={{ borderColor: 'var(--vg-line2)', background: 'var(--vg-surf)' }}>
       <div style={{ position: 'relative', flexShrink: 0 }}>
-        <button
+        <button type="button"
           onClick={() => setShowColorPicker(!showColorPicker)}
           style={{ width: 28, height: 28, borderRadius: 8, background: color, border: '2px solid var(--border-primary)', cursor: 'pointer' }}
           title={t('vacay.calendarColor')}
@@ -576,7 +576,7 @@ function AddCalendarForm({ countries, calendarType, onAdd, onCancel, defaultColo
         {showColorPicker && (
           <div style={{ position: 'absolute', top: 34, left: 0, zIndex: 50, background: 'var(--bg-card)', border: '1px solid var(--border-primary)', borderRadius: 12, padding: 8, boxShadow: '0 8px 24px rgba(0,0,0,0.12)', display: 'grid', gridTemplateColumns: 'repeat(4, 1fr)', gap: 4, width: 120 }}>
             {PRESET_COLORS.map(c => (
-              <button key={c} onClick={() => { setColor(c); setShowColorPicker(false) }}
+              <button type="button" key={c} onClick={() => { setColor(c); setShowColorPicker(false) }}
                 style={{ width: 24, height: 24, borderRadius: 6, background: c, border: color === c ? '2px solid var(--text-primary)' : '2px solid transparent', cursor: 'pointer' }} />
             ))}
           </div>
@@ -607,7 +607,7 @@ function AddCalendarForm({ countries, calendarType, onAdd, onCancel, defaultColo
           />
         )}
         <div className="flex gap-1.5 pt-0.5">
-          <button
+          <button type="button"
             disabled={!canAdd}
             aria-busy={loadingRegions}
             onClick={() => onAdd({ region: region || selectedCountry, color, label: label.trim() || null })}
@@ -616,7 +616,7 @@ function AddCalendarForm({ countries, calendarType, onAdd, onCancel, defaultColo
             {loadingRegions && <Loader2 size={12} className="animate-spin" />}
             {t('vacay.add')}
           </button>
-          <button
+          <button type="button"
             onClick={onCancel}
             className="text-xs px-2 py-1.5 rounded-md transition-colors bg-surface-secondary text-content-muted"
           >
diff --git a/client/src/components/Vacay/VacaySharedCalendars.tsx b/client/src/components/Vacay/VacaySharedCalendars.tsx
index 060c7e3e8..59d903f8b 100644
--- a/client/src/components/Vacay/VacaySharedCalendars.tsx
+++ b/client/src/components/Vacay/VacaySharedCalendars.tsx
@@ -61,7 +61,7 @@ export default function VacaySharedCalendars() {
     <div className="vg-card rounded-[22px]" style={{ padding: '14px 18px' }}>
       <div className="flex items-center justify-between mb-2">
         <span style={{ fontSize: 11, fontWeight: 600, textTransform: 'uppercase', letterSpacing: '0.14em', color: 'var(--vg-ink3)' }}>{t('vacay.sharedCalendars')}</span>
-        <button onClick={() => { setShowShare(true); loadAvailable() }}
+        <button type="button" onClick={() => { setShowShare(true); loadAvailable() }}
           className="w-7 h-7 rounded-lg flex items-center justify-center transition-colors"
           style={{ color: 'var(--vg-ink3)' }}
           title={t('vacay.shareCalendar')}>
@@ -88,7 +88,7 @@ export default function VacaySharedCalendars() {
               </span>
               <VacayBadge label={t('vacay.viewOnly')} />
               <span className="ml-auto flex items-center gap-1">
-                <button onClick={e => { e.stopPropagation(); handleRemove(s.id) }}
+                <button type="button" onClick={e => { e.stopPropagation(); handleRemove(s.id) }}
                   className="opacity-0 group-hover:opacity-100 w-5 h-5 rounded flex items-center justify-center transition-all"
                   style={{ color: 'var(--vg-ink3)' }}
                   title={t('vacay.remove')}>
@@ -115,7 +115,7 @@ export default function VacaySharedCalendars() {
               <span className="truncate min-w-0" style={{ fontSize: 13, color: 'var(--vg-ink2)' }}>
                 {s.username}
               </span>
-              <button onClick={() => handleRemove(s.id)}
+              <button type="button" onClick={() => handleRemove(s.id)}
                 className="ml-auto opacity-0 group-hover:opacity-100 text-[10px] px-1.5 py-0.5 rounded transition-all"
                 style={{ color: 'var(--vg-ink3)' }}>
                 {t('vacay.stopSharing')}
@@ -133,7 +133,7 @@ export default function VacaySharedCalendars() {
             onClick={e => e.stopPropagation()}>
             <div className="flex items-center justify-between p-5 border-b border-edge-secondary">
               <h2 className="text-base font-semibold text-content">{t('vacay.shareCalendar')}</h2>
-              <button onClick={() => setShowShare(false)} className="p-1.5 rounded-lg transition-colors text-content-faint">
+              <button type="button" onClick={() => setShowShare(false)} className="p-1.5 rounded-lg transition-colors text-content-faint">
                 <X size={16} />
               </button>
             </div>
@@ -151,10 +151,10 @@ export default function VacaySharedCalendars() {
                 />
               )}
               <div className="flex gap-3 justify-end pt-2">
-                <button onClick={() => setShowShare(false)} className="px-4 py-2 text-sm rounded-lg text-content-muted border border-edge">
+                <button type="button" onClick={() => setShowShare(false)} className="px-4 py-2 text-sm rounded-lg text-content-muted border border-edge">
                   {t('common.cancel')}
                 </button>
-                <button onClick={handleShare} disabled={!selectedUser || sharing}
+                <button type="button" onClick={handleShare} disabled={!selectedUser || sharing}
                   className="px-4 py-2 text-sm rounded-lg transition-colors flex items-center gap-1.5 disabled:opacity-40 bg-content text-surface-card">
                   {sharing && <Loader2 size={13} className="animate-spin" />}
                   {t('vacay.share')}
diff --git a/client/src/components/Vacay/VacayStats.tsx b/client/src/components/Vacay/VacayStats.tsx
index 0e32961eb..136ac1c41 100644
--- a/client/src/components/Vacay/VacayStats.tsx
+++ b/client/src/components/Vacay/VacayStats.tsx
@@ -49,7 +49,7 @@ export default function VacayStats() {
     <div className="vg-card rounded-[22px]" style={{ padding: '14px 18px' }}>
       {/* The whole header is the fold handle — the sidebar gets long once several
           people are fused in, and this card is the one you stop needing. */}
-      <button
+      <button type="button"
         onClick={toggleCollapsed}
         aria-expanded={!collapsed}
         className={`w-full flex items-start gap-2 text-left ${collapsed ? '' : 'mb-2.5'}`}
@@ -116,7 +116,7 @@ function StatCard({ stat: s, isMe, canEdit, selectedYear, isShiftedYear, onSave,
 
   const handleSave = () => {
     setEditing(false)
-    const days = parseInt(String(localDays))
+    const days = Number.parseInt(String(localDays))
     if (!isNaN(days) && days >= 0 && days <= 365 && days !== s.vacation_days) {
       onSave(selectedYear, days, s.user_id)
     }
diff --git a/client/src/components/shared/ConfirmDialog.tsx b/client/src/components/shared/ConfirmDialog.tsx
index d0feab2ba..c2adb84bc 100644
--- a/client/src/components/shared/ConfirmDialog.tsx
+++ b/client/src/components/shared/ConfirmDialog.tsx
@@ -76,13 +76,13 @@ export default function ConfirmDialog({
         </div>
 
         <div className="flex justify-end gap-3 mt-6">
-          <button
+          <button type="button"
             onClick={onClose}
             className="px-4 py-2 text-sm font-medium rounded-lg transition-colors text-content-secondary border border-edge-secondary"
           >
             {cancelLabel || t('common.cancel')}
           </button>
-          <button
+          <button type="button"
             onClick={() => { runConfirm(onConfirm); onClose() }}
             className={`px-4 py-2 text-sm font-medium rounded-lg transition-colors text-white ${
               danger ? 'bg-red-600 hover:bg-red-700' : 'bg-blue-600 hover:bg-blue-700'
diff --git a/client/src/components/shared/ContextMenu.tsx b/client/src/components/shared/ContextMenu.tsx
index f98965c16..b6c4c9ec6 100644
--- a/client/src/components/shared/ContextMenu.tsx
+++ b/client/src/components/shared/ContextMenu.tsx
@@ -79,7 +79,7 @@ export function ContextMenu({ menu, onClose }: ContextMenuProps) {
         if (item.divider) return <div key={i} style={{ height: 1, background: 'var(--border-faint)', margin: '3px 6px' }} />
         const Icon = item.icon
         return (
-          <button key={i} onClick={() => { item.onClick?.(); onClose() }} style={{
+          <button type="button" key={i} onClick={() => { item.onClick?.(); onClose() }} style={{
             display: 'flex', alignItems: 'center', gap: 8, width: '100%',
             padding: '7px 10px', borderRadius: 7, border: 'none',
             background: 'none', cursor: 'pointer', fontFamily: 'inherit',
diff --git a/client/src/components/shared/CopyTripDialog.tsx b/client/src/components/shared/CopyTripDialog.tsx
index 5c79324f5..a97810e59 100644
--- a/client/src/components/shared/CopyTripDialog.tsx
+++ b/client/src/components/shared/CopyTripDialog.tsx
@@ -88,13 +88,13 @@ export default function CopyTripDialog({ isOpen, tripTitle, onClose, onConfirm }
         </div>
 
         <div className="flex justify-end gap-3 mt-5">
-          <button
+          <button type="button"
             onClick={onClose}
             className="px-4 py-2 text-sm font-medium rounded-lg transition-colors text-content-secondary border border-edge-secondary"
           >
             {t('common.cancel')}
           </button>
-          <button
+          <button type="button"
             onClick={() => { onConfirm(); onClose() }}
             className="px-4 py-2 text-sm font-medium rounded-lg transition-opacity hover:opacity-90 bg-content text-surface-card"
           >
diff --git a/client/src/components/shared/CustomDateTimePicker.tsx b/client/src/components/shared/CustomDateTimePicker.tsx
index fc3467e16..bfaf285d5 100644
--- a/client/src/components/shared/CustomDateTimePicker.tsx
+++ b/client/src/components/shared/CustomDateTimePicker.tsx
@@ -227,7 +227,7 @@ export function CustomDatePicker({
     if (nums.length !== 3) return;
 
     // nachher:
-    const get = (field: 'day' | 'month' | 'year') => parseInt(nums[order.indexOf(field)]);
+    const get = (field: 'day' | 'month' | 'year') => Number.parseInt(nums[order.indexOf(field)]);
     let d = get('day'),
       m = get('month');
     const y = get('year');
diff --git a/client/src/components/shared/CustomTimePicker.tsx b/client/src/components/shared/CustomTimePicker.tsx
index 2c8c0932a..e1a21f7e5 100644
--- a/client/src/components/shared/CustomTimePicker.tsx
+++ b/client/src/components/shared/CustomTimePicker.tsx
@@ -101,16 +101,16 @@ export default function CustomTimePicker({ value, onChange, placeholder = '00:00
     const clean = raw.replace(/[^0-9:]/g, '')
     if (/^\d{1,2}:\d{2}$/.test(clean)) {
       const [hh, mm] = clean.split(':')
-      const h = Math.min(23, Math.max(0, parseInt(hh)))
-      const m = Math.min(59, Math.max(0, parseInt(mm)))
+      const h = Math.min(23, Math.max(0, Number.parseInt(hh)))
+      const m = Math.min(59, Math.max(0, Number.parseInt(mm)))
       onChange(String(h).padStart(2, '0') + ':' + String(m).padStart(2, '0'))
     } else if (/^\d{3,4}$/.test(clean)) {
       const s = clean.padStart(4, '0')
-      const h = Math.min(23, Math.max(0, parseInt(s.slice(0, 2))))
-      const m = Math.min(59, Math.max(0, parseInt(s.slice(2))))
+      const h = Math.min(23, Math.max(0, Number.parseInt(s.slice(0, 2))))
+      const m = Math.min(59, Math.max(0, Number.parseInt(s.slice(2))))
       onChange(String(h).padStart(2, '0') + ':' + String(m).padStart(2, '0'))
     } else if (/^\d{1,2}$/.test(clean)) {
-      const h = Math.min(23, Math.max(0, parseInt(clean)))
+      const h = Math.min(23, Math.max(0, Number.parseInt(clean)))
       onChange(String(h).padStart(2, '0') + ':00')
     }
   }
diff --git a/client/src/components/shared/Modal.tsx b/client/src/components/shared/Modal.tsx
index a33dd7ed6..53b51eb49 100644
--- a/client/src/components/shared/Modal.tsx
+++ b/client/src/components/shared/Modal.tsx
@@ -81,7 +81,7 @@ export default function Modal({
         <div className="flex items-center justify-between p-6 flex-shrink-0 border-b border-edge-secondary">
           <h2 className="text-lg font-semibold text-content">{title}</h2>
           {!hideCloseButton && (
-            <button
+            <button type="button"
               onClick={onClose}
               className="p-2 rounded-lg text-slate-400 hover:text-slate-600 hover:bg-slate-100 transition-colors"
             >
diff --git a/client/src/components/shared/NavigationMenu.tsx b/client/src/components/shared/NavigationMenu.tsx
index 02341a93b..b983bf120 100644
--- a/client/src/components/shared/NavigationMenu.tsx
+++ b/client/src/components/shared/NavigationMenu.tsx
@@ -106,7 +106,7 @@ export function NavigationMenu({ targets, anchor, onClose, title }: NavigationMe
         </div>
       )}
       {targets.map(target => (
-        <button
+        <button type="button"
           key={target.id}
           role="menuitem"
           onClick={() => { openNavigationTarget(target); onClose() }}
diff --git a/client/src/components/shared/SlidingTabs.tsx b/client/src/components/shared/SlidingTabs.tsx
index b6f41d114..860d229b8 100644
--- a/client/src/components/shared/SlidingTabs.tsx
+++ b/client/src/components/shared/SlidingTabs.tsx
@@ -125,7 +125,7 @@ export function SlidingTabs<T extends string>({
           whiteSpace: 'nowrap',
         }
         return (
-          <button
+          <button type="button"
             key={tab.id}
             ref={el => { tabRefs.current.set(tab.id, el) }}
             onClick={() => onChange(tab.id)}
diff --git a/client/src/components/shared/Toast.tsx b/client/src/components/shared/Toast.tsx
index 51284395b..9279a1e69 100644
--- a/client/src/components/shared/Toast.tsx
+++ b/client/src/components/shared/Toast.tsx
@@ -129,7 +129,7 @@ export function ToastContainer() {
             }}>
               {toast.message}
             </span>
-            <button
+            <button type="button"
               onClick={() => removeToast(toast.id)}
               className="nomad-toast-close"
               style={{
diff --git a/client/src/hooks/useResizablePanels.ts b/client/src/hooks/useResizablePanels.ts
index 943d9f796..ba53a2b6c 100644
--- a/client/src/hooks/useResizablePanels.ts
+++ b/client/src/hooks/useResizablePanels.ts
@@ -4,8 +4,8 @@ const MIN_SIDEBAR = 200
 const MAX_SIDEBAR = 520
 
 export function useResizablePanels() {
-  const [leftWidth, setLeftWidth] = useState<number>(() => parseInt(localStorage.getItem('sidebarLeftWidth') || '') || 340)
-  const [rightWidth, setRightWidth] = useState<number>(() => parseInt(localStorage.getItem('sidebarRightWidth') || '') || 300)
+  const [leftWidth, setLeftWidth] = useState<number>(() => Number.parseInt(localStorage.getItem('sidebarLeftWidth') || '') || 340)
+  const [rightWidth, setRightWidth] = useState<number>(() => Number.parseInt(localStorage.getItem('sidebarRightWidth') || '') || 300)
   const [leftCollapsed, setLeftCollapsed] = useState(false)
   const [rightCollapsed, setRightCollapsed] = useState(false)
   const isResizingLeft = useRef(false)
diff --git a/client/src/mobile/screens/admin/MAdminBackupPanel.tsx b/client/src/mobile/screens/admin/MAdminBackupPanel.tsx
index e45493c26..ce2478f44 100644
--- a/client/src/mobile/screens/admin/MAdminBackupPanel.tsx
+++ b/client/src/mobile/screens/admin/MAdminBackupPanel.tsx
@@ -386,7 +386,7 @@ export default function MAdminBackupPanel() {
                 >
                   <select
                     value={String(autoSettings.hour)}
-                    onChange={e => handleAutoSettingsChange('hour', parseInt(e.target.value, 10))}
+                    onChange={e => handleAutoSettingsChange('hour', Number.parseInt(e.target.value, 10))}
                     className={SELECT_CLASS}
                   >
                     {HOURS.map(h => {
@@ -426,7 +426,7 @@ export default function MAdminBackupPanel() {
                 <MAdminField label={t('backup.auto.dayOfMonth')} hint={t('backup.auto.dayOfMonthHint')}>
                   <select
                     value={String(autoSettings.day_of_month)}
-                    onChange={e => handleAutoSettingsChange('day_of_month', parseInt(e.target.value, 10))}
+                    onChange={e => handleAutoSettingsChange('day_of_month', Number.parseInt(e.target.value, 10))}
                     className={SELECT_CLASS}
                   >
                     {DAYS_OF_MONTH.map(d => (
diff --git a/client/src/mobile/screens/admin/MAdminPluginsPanel.tsx b/client/src/mobile/screens/admin/MAdminPluginsPanel.tsx
index f1cd670d9..e713e2158 100644
--- a/client/src/mobile/screens/admin/MAdminPluginsPanel.tsx
+++ b/client/src/mobile/screens/admin/MAdminPluginsPanel.tsx
@@ -187,7 +187,7 @@ const PERM_KEYS = PLUGIN_PERMISSIONS
 const KNOWN_TYPES = ['widget', 'page', 'integration', 'trip-page']
 
 function isNewer(a: string, b: string): boolean {
-  const nums = (v: string) => v.split('-')[0].split('.').map(n => parseInt(n, 10) || 0)
+  const nums = (v: string) => v.split('-')[0].split('.').map(n => Number.parseInt(n, 10) || 0)
   const pa = nums(a), pb = nums(b)
   for (let i = 0; i < 3; i++) {
     const x = pa[i] || 0, y = pb[i] || 0
@@ -850,7 +850,7 @@ export default function MAdminPluginsPanel() {
             <div className={`flex items-center gap-2.5 rounded-[18px] border px-3.5 py-2.5 ${PENDING_CARD}`}>
               <ArrowUpCircle size={16} className="shrink-0 text-[color:var(--m-st-pending)]" />
               <span className="text-[0.6875rem] text-m-muted">{t('admin.plugins.updatesAvailable', { count: updatable.length })}</span>
-              <button onClick={() => updatable.forEach(runUpdate)}
+              <button type="button" onClick={() => updatable.forEach(runUpdate)}
                 className="ml-auto rounded-full bg-[color:var(--m-st-pending)] px-3 py-1.5 text-[0.6875rem] font-bold text-white">
                 {t('admin.plugins.updateAll')}
               </button>
@@ -956,7 +956,7 @@ export default function MAdminPluginsPanel() {
                 {egressFor.hosts.map(h => (
                   <div key={h} className="flex items-center justify-between gap-2 rounded-xl border border-[color:var(--m-rowbr)] px-3 py-2">
                     <span className="break-all font-mono text-sm text-m-ink">{h}</span>
-                    <button
+                    <button type="button"
                       disabled={egressSaving}
                       onClick={() => saveEgress(egressFor.hosts.filter(x => x !== h))}
                       className="text-m-faint disabled:opacity-50"
@@ -1163,7 +1163,7 @@ function InstalledRow({ p, t, busy, hasUpdate, latestVer, blocked, onToggle, onU
         <div className="mt-2 flex items-center gap-1.5 text-[11.5px] text-[color:var(--m-st-pending)]">
           <ShieldAlert size={13} className="shrink-0" />
           <span className="truncate">{t('admin.plugins.updateBlocked', { reason: p.updateBlock.detail ?? p.updateBlock.code })}</span>
-          <button onClick={onReviewBlock}
+          <button type="button" onClick={onReviewBlock}
             className="shrink-0 font-semibold underline underline-offset-2">
             {t('admin.plugins.reviewBlock')}
           </button>
@@ -1186,7 +1186,7 @@ function InstalledRow({ p, t, busy, hasUpdate, latestVer, blocked, onToggle, onU
               Actionable, and warning-toned until at least one host exists, because
               until then the plugin cannot reach anything and looks silently broken. */}
           {p.operatorEgress && (
-            <button
+            <button type="button"
               onClick={onEgress}
               title={t('admin.plugins.allowedHosts.hint')}
               className={`inline-flex items-center gap-1.5 rounded-md border px-2 py-[3px] text-[11px] font-medium ${p.egressHostCount > 0 ? CHIP_INFO : CHIP_PENDING}`}
@@ -1212,7 +1212,7 @@ function InstalledRow({ p, t, busy, hasUpdate, latestVer, blocked, onToggle, onU
 
       {hasUpdate && (
         <div className="mt-2.5 border-t border-[color:var(--m-rowbr)] pt-2.5">
-          <button onClick={onUpdate} disabled={busy === p.id} title={t('admin.plugins.updateTo', { version: latestVer })}
+          <button type="button" onClick={onUpdate} disabled={busy === p.id} title={t('admin.plugins.updateTo', { version: latestVer })}
             className={`inline-flex items-center gap-1.5 rounded-full border px-3 py-1.5 text-[11.5px] font-bold disabled:opacity-50 ${CHIP_PENDING}`}>
             <ArrowUpCircle size={13} /> {t('admin.plugins.updateTo', { version: latestVer })}
           </button>
@@ -1267,7 +1267,7 @@ function EmptyState({ t, onDiscover }: { t: T; onDiscover: () => void }) {
         <PackageOpen size={26} className="text-m-faint" />
       </div>
       <p className="text-sm font-medium text-m-muted">{t('admin.plugins.empty')}</p>
-      <button onClick={onDiscover} className={`mt-4 ${ACT_PILL}`}>
+      <button type="button" onClick={onDiscover} className={`mt-4 ${ACT_PILL}`}>
         <Download size={14} /> {t('admin.plugins.tabDiscover')}
       </button>
     </div>
@@ -1340,7 +1340,7 @@ function RegistryList({ items, onInstall, onOpenDetail, busy, t, installedIds, f
                     <Download size={11} /> {formatCompactCount(item.downloadCount)}
                   </span>
                 )}
-                <button onClick={e => { e.stopPropagation(); onInstall(item.id, offer.version) }}
+                <button type="button" onClick={e => { e.stopPropagation(); onInstall(item.id, offer.version) }}
                   disabled={busy === item.id || installed || offer.blocked}
                   title={installed ? undefined : offer.title}
                   className={`ml-auto ${ACT_PILL}`}>
@@ -1401,7 +1401,7 @@ function PluginDetailSheet({ item, installed, busy, onInstall, onClose, t, local
       <div className="relative flex-none">
         <Screenshot url={item.screenshotUrl} className="aspect-[16/9] w-full" iconSize={36} />
         <div className="absolute inset-0 bg-gradient-to-t from-black/50 to-transparent" />
-        <button onClick={onClose} aria-label={t('common.close')} className="absolute right-3 top-3 grid h-8 w-8 place-items-center rounded-lg bg-black/40 text-white"><X size={16} /></button>
+        <button type="button" onClick={onClose} aria-label={t('common.close')} className="absolute right-3 top-3 grid h-8 w-8 place-items-center rounded-lg bg-black/40 text-white"><X size={16} /></button>
       </div>
 
       <div className="min-h-0 flex-1 overflow-y-auto">
@@ -1416,7 +1416,7 @@ function PluginDetailSheet({ item, installed, busy, onInstall, onClose, t, local
             </div>
             <p className="mt-0.5 text-[12.5px] text-m-faint">{item.author}{item.latest ? ` · v${item.latest}` : ''}</p>
           </div>
-          <button onClick={() => onInstall(item.id, offer.version)}
+          <button type="button" onClick={() => onInstall(item.id, offer.version)}
             disabled={busy === item.id || installed || offer.blocked}
             title={installed ? undefined : offer.title}
             className={`${ACT_PILL} self-end`}>
@@ -1711,7 +1711,7 @@ function DependencyResolveSheet({ data, t, busy, installedIds, onDownload, onClo
                     : t('admin.plugins.dep.requires', { version: r.constraint })}
                 </div>
               </div>
-              <button onClick={() => onDownload(r.id, r.constraint)} disabled={busy}
+              <button type="button" onClick={() => onDownload(r.id, r.constraint)} disabled={busy}
                 className={`shrink-0 ${ACT_PILL}`}>
                 <Download size={13} /> {r.installed ? t('admin.plugins.dep.update') : t('admin.plugins.dep.download')}
               </button>
@@ -1748,7 +1748,7 @@ function SecurityInfo({ t }: { t: T }) {
         <ShieldCheck size={14} className="mt-0.5 shrink-0 text-m-faint" />
         <p className="text-xs text-m-muted">{t('admin.plugins.reviewedMeaning')}</p>
       </div>
-      <button onClick={() => setOpen(o => !o)}
+      <button type="button" onClick={() => setOpen(o => !o)}
         className="flex w-full items-center justify-between gap-2 border-t border-[color:var(--m-rowbr)] px-4 py-3 text-xs font-medium text-m-muted">
         <span className="flex items-center gap-2"><Lock size={13} className="shrink-0" /> <span className="text-left">{t('admin.plugins.security.title')}</span></span>
         <ChevronDown size={15} className={`shrink-0 transition-transform ${open ? 'rotate-180' : ''}`} />
diff --git a/client/src/mobile/screens/dashboard/MDashWidgets.tsx b/client/src/mobile/screens/dashboard/MDashWidgets.tsx
index 1dd35ecad..e385b5142 100644
--- a/client/src/mobile/screens/dashboard/MDashWidgets.tsx
+++ b/client/src/mobile/screens/dashboard/MDashWidgets.tsx
@@ -153,7 +153,7 @@ function MCurrencyWidget(): React.ReactElement {
 
   const currencies = rates ? Object.keys(rates).sort() : [...CURRENCIES]
   const rate = rates?.[to] ?? null
-  const converted = rate != null ? (parseFloat(amount.replace(',', '.')) || 0) * rate : null
+  const converted = rate != null ? (Number.parseFloat(amount.replace(',', '.')) || 0) * rate : null
   const swap = () => { setFrom(to); setTo(from) }
 
   return (
diff --git a/client/src/mobile/screens/journey/MJourneyEntrySheet.tsx b/client/src/mobile/screens/journey/MJourneyEntrySheet.tsx
index 16b975c0e..ee6c8ef1a 100644
--- a/client/src/mobile/screens/journey/MJourneyEntrySheet.tsx
+++ b/client/src/mobile/screens/journey/MJourneyEntrySheet.tsx
@@ -139,7 +139,7 @@ export default function MJourneyEntrySheet({
       if (group.provider === activeProvider) group.assetIds.forEach(assetId => providerExistingAssetIds.add(assetId))
     })
   }
-  const contextLocation = isValidGeoPoint({ lat: locationLat ?? NaN, lng: locationLng ?? NaN })
+  const contextLocation = isValidGeoPoint({ lat: locationLat ?? Number.NaN, lng: locationLng ?? Number.NaN })
     ? { lat: locationLat!, lng: locationLng!, name: locationName || undefined }
     : null
 
diff --git a/client/src/mobile/screens/settings/MSettingsAppearance.tsx b/client/src/mobile/screens/settings/MSettingsAppearance.tsx
index 609030d77..79eb81fed 100644
--- a/client/src/mobile/screens/settings/MSettingsAppearance.tsx
+++ b/client/src/mobile/screens/settings/MSettingsAppearance.tsx
@@ -24,9 +24,9 @@ function channelLum(v: number): number {
 function relLuminance(hex: string): number {
   const c = hex.replace('#', '')
   const full = c.length === 3 ? c.split('').map((x) => x + x).join('') : c
-  const r = channelLum(parseInt(full.slice(0, 2), 16) / 255)
-  const g = channelLum(parseInt(full.slice(2, 4), 16) / 255)
-  const b = channelLum(parseInt(full.slice(4, 6), 16) / 255)
+  const r = channelLum(Number.parseInt(full.slice(0, 2), 16) / 255)
+  const g = channelLum(Number.parseInt(full.slice(2, 4), 16) / 255)
+  const b = channelLum(Number.parseInt(full.slice(4, 6), 16) / 255)
   return 0.2126 * r + 0.7152 * g + 0.0722 * b
 }
 function contrastRatio(a: string, b: string): number {
diff --git a/client/src/mobile/screens/trip/sheets/MCostSheet.tsx b/client/src/mobile/screens/trip/sheets/MCostSheet.tsx
index 70262ed0e..5bf4cdfca 100644
--- a/client/src/mobile/screens/trip/sheets/MCostSheet.tsx
+++ b/client/src/mobile/screens/trip/sheets/MCostSheet.tsx
@@ -125,8 +125,8 @@ export default function MCostSheet({ tripId, base, people, me, editing, prefill,
   const isTicketMode = splitMode === 'ticket'
   const ticketInfo = useMemo(() => calculateTicketShares(ticketItems), [ticketItems])
 
-  const totalNum = isTicketMode ? ticketInfo.total : (parseFloat(total) || 0)
-  const splitSum = [...participants].reduce((sum, id) => sum + (parseFloat(customAmounts[id]) || 0), 0)
+  const totalNum = isTicketMode ? ticketInfo.total : (Number.parseFloat(total) || 0)
+  const splitSum = [...participants].reduce((sum, id) => sum + (Number.parseFloat(customAmounts[id]) || 0), 0)
   const customBalanced = Math.round(splitSum * 100) === Math.round(totalNum * 100)
   const each = participants.size > 0 ? totalNum / participants.size : 0
   const equalShares = useMemo(
@@ -139,12 +139,12 @@ export default function MCostSheet({ tripId, base, people, me, editing, prefill,
     if (emptyParts.length === 0) return {}
     const enteredSum = [...participants]
       .filter(id => customAmounts[id])
-      .reduce((sum, id) => sum + (parseFloat(customAmounts[id]) || 0), 0)
+      .reduce((sum, id) => sum + (Number.parseFloat(customAmounts[id]) || 0), 0)
     const remaining = Math.max(0, totalNum - enteredSum)
     return splitEqualShares(remaining, emptyParts.map(id => ({ user_id: id })), editing?.id || 0)
   }, [totalNum, participants, customAmounts, editing])
 
-  const ticketValid = ticketItems.length > 0 && ticketItems.every(item => item.name.trim().length > 0 && (parseFloat(item.price) || 0) > 0 && item.participants.size > 0)
+  const ticketValid = ticketItems.length > 0 && ticketItems.every(item => item.name.trim().length > 0 && (Number.parseFloat(item.price) || 0) > 0 && item.participants.size > 0)
   const payersOk = !multiPayer || (payerIds.size > 0 && payersBalanced(payerAmounts, payerIds, totalNum))
   const valid = name.trim().length > 0 && payersOk && (
     isTicketMode
@@ -237,12 +237,12 @@ export default function MCostSheet({ tripId, base, people, me, editing, prefill,
     // server re-derives total_price from the payer sum (CostsPanel.helpers), so
     // dropping the payer would store the entry with a total of 0.
     const payerList = multiPayer
-      ? [...payerIds].map(id => ({ user_id: id, amount: parseFloat(payerAmounts[id]) || 0 })).filter(p => p.amount > 0)
+      ? [...payerIds].map(id => ({ user_id: id, amount: Number.parseFloat(payerAmounts[id]) || 0 })).filter(p => p.amount > 0)
       : payerId > 0 ? [{ user_id: payerId, amount: totalNum }] : []
     const memberList = [...participants].map(id => ({
       user_id: id,
       amount: splitMode === 'custom'
-        ? (parseFloat(customAmounts[id]) || 0)
+        ? (Number.parseFloat(customAmounts[id]) || 0)
         : splitMode === 'ticket'
           ? (ticketInfo.shares[id] || 0)
           : null,
diff --git a/client/src/mobile/screens/trip/sheets/MPlaceEditSheet.tsx b/client/src/mobile/screens/trip/sheets/MPlaceEditSheet.tsx
index 299ed7e28..51c5aa24a 100644
--- a/client/src/mobile/screens/trip/sheets/MPlaceEditSheet.tsx
+++ b/client/src/mobile/screens/trip/sheets/MPlaceEditSheet.tsx
@@ -33,8 +33,8 @@ function findDuplicateName(
 ): string | null {
   const name = form.name.trim().toLowerCase()
   const gid = (form.google_place_id || '').trim()
-  const lat = form.lat ? parseFloat(form.lat) : null
-  const lng = form.lng ? parseFloat(form.lng) : null
+  const lat = form.lat ? Number.parseFloat(form.lat) : null
+  const lng = form.lng ? Number.parseFloat(form.lng) : null
   for (const p of places || []) {
     if (gid && p.google_place_id && p.google_place_id === gid) return p.name || form.name
     if (name && p.name && p.name.trim().toLowerCase() === name) return p.name
@@ -236,8 +236,8 @@ export default function MPlaceEditSheet({ planner, onOpenExpense }: MPlaceEditSh
     try {
       const saved = await handleSavePlace({
         ...form,
-        lat: form.lat ? parseFloat(form.lat) : null,
-        lng: form.lng ? parseFloat(form.lng) : null,
+        lat: form.lat ? Number.parseFloat(form.lat) : null,
+        lng: form.lng ? Number.parseFloat(form.lng) : null,
         category_id: form.category_id || null,
         _pendingFiles: pendingFiles.length > 0 ? pendingFiles : undefined,
       })
diff --git a/client/src/mobile/screens/trip/tabs/MCostsTab.tsx b/client/src/mobile/screens/trip/tabs/MCostsTab.tsx
index 6c7dff27d..6772ca0ef 100644
--- a/client/src/mobile/screens/trip/tabs/MCostsTab.tsx
+++ b/client/src/mobile/screens/trip/tabs/MCostsTab.tsx
@@ -685,7 +685,7 @@ function AddPaymentSheet({ open, onClose, tripId, base, people, me, toast, t, on
     setSaving(false)
   }, [open, me, people])
 
-  const amt = parseFloat(amount.replace(',', '.')) || 0
+  const amt = Number.parseFloat(amount.replace(',', '.')) || 0
   const valid = amt > 0 && fromId !== toId
 
   const save = async () => {
diff --git a/client/src/mobile/screens/trip/tabs/MPackItemSheet.tsx b/client/src/mobile/screens/trip/tabs/MPackItemSheet.tsx
index 820b495bf..930180fdf 100644
--- a/client/src/mobile/screens/trip/tabs/MPackItemSheet.tsx
+++ b/client/src/mobile/screens/trip/tabs/MPackItemSheet.tsx
@@ -87,8 +87,8 @@ export default function MPackItemSheet({
     const trimmedName = name.trim()
     setSaving(true)
     try {
-      const qty = Math.max(1, Math.min(999, parseInt(quantity, 10) || 1))
-      const weightVal = weight.trim() === '' ? null : Math.max(0, parseInt(weight, 10) || 0)
+      const qty = Math.max(1, Math.min(999, Number.parseInt(quantity, 10) || 1))
+      const weightVal = weight.trim() === '' ? null : Math.max(0, Number.parseInt(weight, 10) || 0)
       await tripActions.updatePackingItem(tripId, item.id, {
         name: trimmedName,
         quantity: qty,
diff --git a/client/src/mobile/screens/trip/tabs/MPackingListTab.tsx b/client/src/mobile/screens/trip/tabs/MPackingListTab.tsx
index 65be985a3..aa190c619 100644
--- a/client/src/mobile/screens/trip/tabs/MPackingListTab.tsx
+++ b/client/src/mobile/screens/trip/tabs/MPackingListTab.tsx
@@ -598,8 +598,8 @@ function PackingCategoryCard({
 
   return (
     <div className="mt-[10px] overflow-hidden rounded-2xl border border-[color:var(--m-rowbr)] bg-m-sheetop">
-      {/* A <div role="button"> rather than a real <button> — the rename input and
-          the assign/menu triggers below are interactive elements a <button> may
+      {/* A <div role="button"> rather than a real <button type="button"> — the rename input and
+          the assign/menu triggers below are interactive elements a <button type="button"> may
           not contain (invalid HTML); this stays keyboard-operable via onKeyDown. */}
       <div
         role="button"
diff --git a/client/src/mobile/screens/trip/tabs/costsModel.ts b/client/src/mobile/screens/trip/tabs/costsModel.ts
index 03a13528c..181bf8d01 100644
--- a/client/src/mobile/screens/trip/tabs/costsModel.ts
+++ b/client/src/mobile/screens/trip/tabs/costsModel.ts
@@ -196,9 +196,9 @@ export function categoryBreakdown(items: BudgetItem[], ctx: CostsCtx): CostsCate
 /** Category colour at a fixed alpha — the expense card's border tint (spec §3.10: "brC"). */
 export function tint(hex: string, alpha: number): string {
   const clean = hex.replace('#', '')
-  const r = parseInt(clean.slice(0, 2), 16)
-  const g = parseInt(clean.slice(2, 4), 16)
-  const b = parseInt(clean.slice(4, 6), 16)
+  const r = Number.parseInt(clean.slice(0, 2), 16)
+  const g = Number.parseInt(clean.slice(2, 4), 16)
+  const b = Number.parseInt(clean.slice(4, 6), 16)
   return `rgba(${r}, ${g}, ${b}, ${alpha})`
 }
 
diff --git a/client/src/mobile/screens/trip/tabs/listsModel.ts b/client/src/mobile/screens/trip/tabs/listsModel.ts
index 7b54975cc..2ab90a472 100644
--- a/client/src/mobile/screens/trip/tabs/listsModel.ts
+++ b/client/src/mobile/screens/trip/tabs/listsModel.ts
@@ -154,7 +154,9 @@ export function sortTodoRows(items: TodoItem[], sortByPriority: boolean, today:
 export function todoCategories(items: TodoItem[]): string[] {
   const cats = new Set<string>()
   items.forEach(i => { if (i.category) cats.add(i.category) })
-  return Array.from(cats).sort()
+  // Same locale collation as the desktop hook (useTodoList) — a bare .sort() is
+  // byte order and files every accented name behind the whole ASCII range.
+  return Array.from(cats).sort((a, b) => a.localeCompare(b))
 }
 
 /** Open (non-done) item count for a given category — matches the desktop sidebar badge. */
diff --git a/client/src/mobile/screens/vacay/MVacaySettingsSheet.tsx b/client/src/mobile/screens/vacay/MVacaySettingsSheet.tsx
index e5c707dab..32390b574 100644
--- a/client/src/mobile/screens/vacay/MVacaySettingsSheet.tsx
+++ b/client/src/mobile/screens/vacay/MVacaySettingsSheet.tsx
@@ -348,7 +348,7 @@ function YearTypeRows() {
               value={String(yearSettings.year_start_month)}
               placeholder={t('vacay.yearStartMonth')}
               options={monthOptions}
-              onChange={v => save({ year_start_month: parseInt(v, 10) })}
+              onChange={v => save({ year_start_month: Number.parseInt(v, 10) })}
             />
           </span>
           <span className="w-[86px] flex-none">
@@ -356,7 +356,7 @@ function YearTypeRows() {
               value={String(yearSettings.year_start_day)}
               placeholder={t('vacay.yearStartDay')}
               options={Array.from({ length: monthDayCap(yearSettings.year_start_month) }, (_, i) => ({ value: String(i + 1), label: String(i + 1) }))}
-              onChange={v => save({ year_start_day: parseInt(v, 10) })}
+              onChange={v => save({ year_start_day: Number.parseInt(v, 10) })}
             />
           </span>
         </div>
diff --git a/client/src/mobile/screens/vacay/vacayDayModel.ts b/client/src/mobile/screens/vacay/vacayDayModel.ts
index 1f70e45c8..2db106b4d 100644
--- a/client/src/mobile/screens/vacay/vacayDayModel.ts
+++ b/client/src/mobile/screens/vacay/vacayDayModel.ts
@@ -38,7 +38,7 @@ export interface DayVisualContext {
 function hexToHsl(hex: string): { h: number; s: number; l: number } | null {
   const m = /^#([0-9a-f]{6})$/i.exec(hex.trim())
   if (!m) return null
-  const n = parseInt(m[1], 16)
+  const n = Number.parseInt(m[1], 16)
   const r = ((n >> 16) & 255) / 255
   const g = ((n >> 8) & 255) / 255
   const b = (n & 255) / 255
diff --git a/client/src/pages/AdminPage.tsx b/client/src/pages/AdminPage.tsx
index 60f511300..5093ae9fc 100644
--- a/client/src/pages/AdminPage.tsx
+++ b/client/src/pages/AdminPage.tsx
@@ -104,7 +104,7 @@ function AdminPageDesktop(): React.ReactElement {
                 <p className="text-sm font-semibold text-amber-900">Demo Baseline</p>
                 <p className="text-xs text-amber-700">Save current state as the hourly reset point. All admin trips and settings will be preserved.</p>
               </div>
-              <button
+              <button type="button"
                 onClick={async () => {
                   try {
                     await adminApi.saveDemoBaseline()
diff --git a/client/src/pages/AtlasPage.tsx b/client/src/pages/AtlasPage.tsx
index ca123e61f..02800f7af 100644
--- a/client/src/pages/AtlasPage.tsx
+++ b/client/src/pages/AtlasPage.tsx
@@ -183,7 +183,7 @@ function AtlasPageDesktop(): React.ReactElement {
 
             {confirmAction.type === 'choose' && (
               <div style={{ display: 'flex', flexDirection: 'column', gap: 8 }}>
-                <button onClick={async () => {
+                <button type="button" onClick={async () => {
                   try {
                     await apiClient.post(`/addons/atlas/country/${confirmAction.code}/mark`)
                     setData(prev => (prev ? withCountryMarkedVisited(prev, confirmAction.code) : prev))
@@ -217,7 +217,7 @@ function AtlasPageDesktop(): React.ReactElement {
                   const wishlistItems = bucketList.filter(b => b.country_code === confirmAction.code)
                   if (wishlistItems.length === 0) return null
                   return (
-                    <button onClick={async () => {
+                    <button type="button" onClick={async () => {
                       await Promise.all(wishlistItems.map(item => handleDeleteBucketItem(item.id)))
                       setConfirmAction(null)
                     }}
@@ -285,12 +285,12 @@ function AtlasPageDesktop(): React.ReactElement {
               <>
                 <p className="text-content-muted" style={{ margin: '0 0 20px', fontSize: 'calc(13px * var(--fs-scale-body, 1))' }}>{t('atlas.confirmUnmark')}</p>
                 <div style={{ display: 'flex', gap: 8, justifyContent: 'center' }}>
-                  <button onClick={() => setConfirmAction(null)}
+                  <button type="button" onClick={() => setConfirmAction(null)}
                     className="border border-edge text-content-muted"
                     style={{ padding: '8px 20px', borderRadius: 10, background: 'none', fontSize: 'calc(13px * var(--fs-scale-body, 1))', cursor: 'pointer', fontFamily: 'inherit' }}>
                     {t('common.cancel')}
                   </button>
-                  <button onClick={executeConfirmAction}
+                  <button type="button" onClick={executeConfirmAction}
                     className="bg-[#ef4444] text-white"
                     style={{ padding: '8px 20px', borderRadius: 10, border: 'none', fontSize: 'calc(13px * var(--fs-scale-body, 1))', fontWeight: 600, cursor: 'pointer', fontFamily: 'inherit' }}>
                     {t('atlas.unmark')}
@@ -306,7 +306,7 @@ function AtlasPageDesktop(): React.ReactElement {
                 )}
                 <p className="text-content-muted" style={{ margin: '0 0 20px', fontSize: 'calc(13px * var(--fs-scale-body, 1))' }}>{t('atlas.confirmUnmarkRegion')}</p>
                 <div style={{ display: 'flex', gap: 8, justifyContent: 'center' }}>
-                  <button onClick={() => setConfirmAction(null)}
+                  <button type="button" onClick={() => setConfirmAction(null)}
                     className="border border-edge text-content-muted"
                     style={{ padding: '8px 20px', borderRadius: 10, background: 'none', fontSize: 'calc(13px * var(--fs-scale-body, 1))', cursor: 'pointer', fontFamily: 'inherit' }}>
                     {t('common.cancel')}
@@ -391,7 +391,7 @@ function AtlasPageDesktop(): React.ReactElement {
                     style={{ padding: '8px 20px', borderRadius: 10, background: 'none', fontSize: 'calc(13px * var(--fs-scale-body, 1))', cursor: 'pointer', fontFamily: 'inherit' }}>
                     {t('common.back')}
                   </button>
-                  <button onClick={async () => {
+                  <button type="button" onClick={async () => {
                     const targetDate = bucketMonth > 0 && bucketYear > 0 ? `${bucketYear}-${String(bucketMonth).padStart(2, '0')}` : null
                     // #1898: one entry per target date. The dialog stays open on a
                     // duplicate so another month can be picked right away.
@@ -424,12 +424,12 @@ function AtlasPageDesktop(): React.ReactElement {
               <>
                 <p className="text-content-muted" style={{ margin: '0 0 20px', fontSize: 'calc(13px * var(--fs-scale-body, 1))' }}>{t('atlas.confirmMark')}</p>
                 <div style={{ display: 'flex', gap: 8, justifyContent: 'center' }}>
-                  <button onClick={() => setConfirmAction(null)}
+                  <button type="button" onClick={() => setConfirmAction(null)}
                     className="border border-edge text-content-muted"
                     style={{ padding: '8px 20px', borderRadius: 10, background: 'none', fontSize: 'calc(13px * var(--fs-scale-body, 1))', cursor: 'pointer', fontFamily: 'inherit' }}>
                     {t('common.cancel')}
                   </button>
-                  <button onClick={executeConfirmAction}
+                  <button type="button" onClick={executeConfirmAction}
                     className="bg-content text-white"
                     style={{ padding: '8px 20px', borderRadius: 10, border: 'none', fontSize: 'calc(13px * var(--fs-scale-body, 1))', fontWeight: 600, cursor: 'pointer', fontFamily: 'inherit' }}>
                     {t('atlas.markVisited')}
@@ -506,7 +506,7 @@ function SidebarContent({ data, stats, countries, selectedCountry, countryDetail
   const tabBar = (
     <div style={{ display: 'flex', gap: 4, padding: '12px 16px 0', marginBottom: 4 }}>
       {[{ id: 'stats', label: t('atlas.statsTab'), icon: Globe }, { id: 'bucket', label: t('atlas.bucketTab'), icon: Star }].map(tab => (
-        <button key={tab.id} onClick={() => setBucketTab(tab.id as any)}
+        <button type="button" key={tab.id} onClick={() => setBucketTab(tab.id as any)}
           style={{
             flex: 1, display: 'flex', alignItems: 'center', justifyContent: 'center', gap: 5,
             padding: '7px 0', borderRadius: 10, border: 'none', cursor: 'pointer', fontFamily: 'inherit',
@@ -552,7 +552,7 @@ function SidebarContent({ data, stats, countries, selectedCountry, countryDetail
             return <span className="text-[9px] mt-0.5 text-center" style={{ color: tf }}>{label}</span>
           })()}
           {!item.target_date && item.notes && <span className="text-[9px] mt-0.5 text-center" style={{ color: tf, maxWidth: 90, overflow: 'hidden', textOverflow: 'ellipsis', whiteSpace: 'nowrap' }}>{item.notes}</span>}
-          <button onClick={() => onDeleteBucket(item.id)}
+          <button type="button" onClick={() => onDeleteBucket(item.id)}
             className="opacity-0 group-hover:opacity-100"
             style={{ position: 'absolute', top: 4, right: 4, background: 'none', border: 'none', cursor: 'pointer', padding: 2, color: tf, display: 'flex', transition: 'opacity 0.15s' }}>
             <X size={10} />
@@ -579,7 +579,7 @@ function SidebarContent({ data, stats, countries, selectedCountry, countryDetail
               style={{ flex: 1, padding: '6px 10px', borderRadius: 8, fontSize: 'calc(12px * var(--fs-scale-body, 1))', fontFamily: 'inherit', outline: 'none', boxSizing: 'border-box' }}
             />
             {!bucketForm.name && (
-              <button onClick={onSearchBucket} disabled={bucketSearching}
+              <button type="button" onClick={onSearchBucket} disabled={bucketSearching}
                 className="bg-accent text-accent-text"
                 style={{ padding: '6px 10px', borderRadius: 8, border: 'none', cursor: 'pointer', display: 'flex', alignItems: 'center' }}>
                 <Search size={12} />
@@ -616,7 +616,7 @@ function SidebarContent({ data, stats, countries, selectedCountry, countryDetail
               zIndex: 99999, borderRadius: 8, boxShadow: '0 4px 12px rgba(0,0,0,0.12)', overflowY: 'auto',
             }}>
               {bucketSearchResults.slice(0, 6).map((r, i) => (
-                <button key={i} onClick={() => onSelectBucketPoi(r)} className="border-b border-edge-faint" style={{ display: 'flex', flexDirection: 'column', gap: 1, width: '100%', padding: '6px 10px', borderTop: 'none', borderLeft: 'none', borderRight: 'none', background: 'none', cursor: 'pointer', textAlign: 'left', fontFamily: 'inherit' }}>
+                <button type="button" key={i} onClick={() => onSelectBucketPoi(r)} className="border-b border-edge-faint" style={{ display: 'flex', flexDirection: 'column', gap: 1, width: '100%', padding: '6px 10px', borderTop: 'none', borderLeft: 'none', borderRight: 'none', background: 'none', cursor: 'pointer', textAlign: 'left', fontFamily: 'inherit' }}>
                   <span className="text-content" style={{ fontSize: 'calc(12px * var(--fs-scale-body, 1))', fontWeight: 500 }}>{r.name}</span>
                   {r.address && <span className="text-content-faint" style={{ fontSize: 'calc(10px * var(--fs-scale-caption, 1))' }}>{r.address}</span>}
                 </button>
@@ -643,12 +643,12 @@ function SidebarContent({ data, stats, countries, selectedCountry, countryDetail
           </div>
         </div>
         <div style={{ display: 'flex', gap: 6, justifyContent: 'flex-end' }}>
-          <button onClick={() => { setShowBucketAdd(false); setBucketForm({ name: '', notes: '', lat: '', lng: '', target_date: '' }); setBucketSearch(''); setBucketSearchResults([]); setBucketPoiMonth(0); setBucketPoiYear(0) }}
+          <button type="button" onClick={() => { setShowBucketAdd(false); setBucketForm({ name: '', notes: '', lat: '', lng: '', target_date: '' }); setBucketSearch(''); setBucketSearchResults([]); setBucketPoiMonth(0); setBucketPoiYear(0) }}
             className="border border-edge text-content-muted"
             style={{ fontSize: 'calc(11px * var(--fs-scale-caption, 1))', padding: '4px 10px', borderRadius: 6, background: 'none', cursor: 'pointer', fontFamily: 'inherit' }}>
             {t('common.cancel')}
           </button>
-          <button onClick={onAddBucket} disabled={!bucketForm.name.trim()}
+          <button type="button" onClick={onAddBucket} disabled={!bucketForm.name.trim()}
             className="bg-[#fbbf24] text-[#1a1a1a]"
             style={{ fontSize: 'calc(11px * var(--fs-scale-caption, 1))', padding: '4px 12px', borderRadius: 6, border: 'none', fontWeight: 600, cursor: 'pointer', fontFamily: 'inherit', opacity: bucketForm.name.trim() ? 1 : 0.5 }}>
             {t('common.add')}
@@ -657,7 +657,7 @@ function SidebarContent({ data, stats, countries, selectedCountry, countryDetail
       </div>
     ) : (
       <div style={{ padding: '4px 16px 8px' }}>
-        <button onClick={() => setShowBucketAdd(true)}
+        <button type="button" onClick={() => setShowBucketAdd(true)}
           className="border border-dashed border-edge"
           style={{ display: 'flex', alignItems: 'center', justifyContent: 'center', gap: 4, width: '100%', padding: '5px 0', borderRadius: 8, background: 'none', fontSize: 'calc(11px * var(--fs-scale-caption, 1))', color: tf, cursor: 'pointer', fontFamily: 'inherit' }}>
           <Plus size={11} /> {t('atlas.addPoi')}
@@ -756,7 +756,7 @@ function SidebarContent({ data, stats, countries, selectedCountry, countryDetail
               <p className="text-[10px] mb-1" style={{ color: tf }}>{countryDetail.places.length} {t('atlas.places')} · {countryDetail.trips.length} {t('atlas.tripPlural')}</p>
               <div className="flex flex-wrap gap-1">
                 {countryDetail.trips.slice(0, 3).map(trip => (
-                  <button key={trip.id} onClick={() => onTripClick(trip.id)}
+                  <button type="button" key={trip.id} onClick={() => onTripClick(trip.id)}
                     className="flex items-center gap-1 px-2 py-0.5 rounded text-[10px] font-semibold transition-opacity hover:opacity-75"
                     style={{ background: bg(0.08), color: tp }}>
                     <Briefcase size={9} style={{ color: tm }} />
@@ -764,7 +764,7 @@ function SidebarContent({ data, stats, countries, selectedCountry, countryDetail
                   </button>
                 ))}
                 {countryDetail.manually_marked && onUnmarkCountry && (
-                  <button onClick={() => onUnmarkCountry(selectedCountry!)}
+                  <button type="button" onClick={() => onUnmarkCountry(selectedCountry!)}
                     className="flex items-center gap-1 px-2 py-0.5 rounded text-[10px] font-semibold transition-opacity hover:opacity-75 bg-[rgba(239,68,68,0.1)] text-[#ef4444]">
                     <X size={9} />
                     {t('atlas.unmark')}
diff --git a/client/src/pages/DashboardPage.tsx b/client/src/pages/DashboardPage.tsx
index dad6a303c..c48f516e6 100644
--- a/client/src/pages/DashboardPage.tsx
+++ b/client/src/pages/DashboardPage.tsx
@@ -151,7 +151,7 @@ function DashboardPageDesktop(): React.ReactElement {
             {loadError && (
               <div className="dash-error" role="alert">
                 <span className="dash-error-txt">{t('dashboard.loadErrorBanner')}</span>
-                <button className="dash-error-retry" onClick={retryLoad}>
+                <button type="button" className="dash-error-retry" onClick={retryLoad}>
                   <RefreshCw size={15} />
                   {t('dashboard.retry')}
                 </button>
@@ -177,11 +177,11 @@ function DashboardPageDesktop(): React.ReactElement {
                 <h3 className="sec-title">{t('dashboard.title')}</h3>
                 <div className="sec-tools">
                   <div className="seg">
-                    <button className={tripFilter === 'planned' ? 'on' : ''} onClick={() => setTripFilter('planned')}>{t('dashboard.filter.planned')}</button>
-                    <button className={tripFilter === 'archive' ? 'on' : ''} onClick={() => setTripFilter('archive')}>{t('dashboard.archived')}</button>
-                    <button className={tripFilter === 'completed' ? 'on' : ''} onClick={() => setTripFilter('completed')}>{t('dashboard.mobile.completed')}</button>
+                    <button type="button" className={tripFilter === 'planned' ? 'on' : ''} onClick={() => setTripFilter('planned')}>{t('dashboard.filter.planned')}</button>
+                    <button type="button" className={tripFilter === 'archive' ? 'on' : ''} onClick={() => setTripFilter('archive')}>{t('dashboard.archived')}</button>
+                    <button type="button" className={tripFilter === 'completed' ? 'on' : ''} onClick={() => setTripFilter('completed')}>{t('dashboard.mobile.completed')}</button>
                   </div>
-                  <button
+                  <button type="button"
                     className="tool-action"
                     aria-label="Subscribe to all trips calendar"
                     title="Subscribe to all trips"
@@ -190,7 +190,7 @@ function DashboardPageDesktop(): React.ReactElement {
                   >
                     <CalendarPlus size={17} />
                   </button>
-                  <button className="tool-action" aria-label={t('dashboard.aria.toggleView')} onClick={toggleViewMode} style={{ width: 38, height: 38, borderRadius: 11 }}>
+                  <button type="button" className="tool-action" aria-label={t('dashboard.aria.toggleView')} onClick={toggleViewMode} style={{ width: 38, height: 38, borderRadius: 11 }}>
                     {viewMode === 'grid' ? <List size={17} /> : <LayoutGrid size={17} />}
                   </button>
                 </div>
@@ -228,7 +228,7 @@ function DashboardPageDesktop(): React.ReactElement {
                   />
                 ))}
                 {tripFilter === 'planned' && !isLoading && (
-                  <button className="add-trip-card" onClick={() => { setEditingTrip(null); setShowForm(true) }}>
+                  <button type="button" className="add-trip-card" onClick={() => { setEditingTrip(null); setShowForm(true) }}>
                     <div>
                       <div className="circ"><Plus size={20} /></div>
                       <div className="ttl">{t('dashboard.newTrip')}</div>
@@ -252,7 +252,7 @@ function DashboardPageDesktop(): React.ReactElement {
         </main>
       </div>
 
-      <button
+      <button type="button"
         className="fab-new-trip"
         onClick={() => { setEditingTrip(null); setShowForm(true) }}
         aria-label={t('dashboard.newTrip')}
@@ -405,10 +405,10 @@ function BoardingPassHero({ trip, bundle, locale, onOpen, onEdit, onCopy, onArch
             {badge}
           </div>
           <div className="hero-tools">
-            <button className="hero-tool" aria-label={t('common.edit')} title={t('common.edit')} onClick={(e) => stop(e, onEdit)}><Edit2 size={17} strokeWidth={2.2} /></button>
-            <button className="hero-tool" aria-label={t('dashboard.aria.duplicate')} title={t('dashboard.aria.duplicate')} onClick={(e) => stop(e, onCopy)}><Copy size={17} strokeWidth={2.2} /></button>
-            <button className="hero-tool" aria-label={archiveLabel} title={archiveLabel} onClick={(e) => stop(e, onArchive)}>{trip.is_archived ? <ArchiveRestore size={17} strokeWidth={2.2} /> : <Archive size={17} strokeWidth={2.2} />}</button>
-            <button className="hero-tool" aria-label={t('common.delete')} title={t('common.delete')} onClick={(e) => stop(e, onDelete)}><Trash2 size={17} strokeWidth={2.2} /></button>
+            <button type="button" className="hero-tool" aria-label={t('common.edit')} title={t('common.edit')} onClick={(e) => stop(e, onEdit)}><Edit2 size={17} strokeWidth={2.2} /></button>
+            <button type="button" className="hero-tool" aria-label={t('dashboard.aria.duplicate')} title={t('dashboard.aria.duplicate')} onClick={(e) => stop(e, onCopy)}><Copy size={17} strokeWidth={2.2} /></button>
+            <button type="button" className="hero-tool" aria-label={archiveLabel} title={archiveLabel} onClick={(e) => stop(e, onArchive)}>{trip.is_archived ? <ArchiveRestore size={17} strokeWidth={2.2} /> : <Archive size={17} strokeWidth={2.2} />}</button>
+            <button type="button" className="hero-tool" aria-label={t('common.delete')} title={t('common.delete')} onClick={(e) => stop(e, onDelete)}><Trash2 size={17} strokeWidth={2.2} /></button>
           </div>
         </div>
 
@@ -559,10 +559,10 @@ function TripCard({ trip, locale, badges, onOpen, onEdit, onCopy, onArchive, onD
           : <div style={{ width: '100%', height: '100%', background: tripGradient(trip.id) }} />}
         <div className={`trip-status ${statusClass}`}><span className="indicator" /> {statusLabel}</div>
         <div className="trip-actions">
-          <button className="trip-action-btn" aria-label={t('common.edit')} title={t('common.edit')} onClick={(e) => stop(e, onEdit)}><Edit2 size={17} strokeWidth={2.2} /></button>
-          <button className="trip-action-btn" aria-label={t('dashboard.aria.duplicate')} title={t('dashboard.aria.duplicate')} onClick={(e) => stop(e, onCopy)}><Copy size={17} strokeWidth={2.2} /></button>
-          <button className="trip-action-btn" aria-label={archiveLabel} title={archiveLabel} onClick={(e) => stop(e, onArchive)}>{trip.is_archived ? <ArchiveRestore size={17} strokeWidth={2.2} /> : <Archive size={17} strokeWidth={2.2} />}</button>
-          <button className="trip-action-btn" aria-label={t('common.delete')} title={t('common.delete')} onClick={(e) => stop(e, onDelete)}><Trash2 size={17} strokeWidth={2.2} /></button>
+          <button type="button" className="trip-action-btn" aria-label={t('common.edit')} title={t('common.edit')} onClick={(e) => stop(e, onEdit)}><Edit2 size={17} strokeWidth={2.2} /></button>
+          <button type="button" className="trip-action-btn" aria-label={t('dashboard.aria.duplicate')} title={t('dashboard.aria.duplicate')} onClick={(e) => stop(e, onCopy)}><Copy size={17} strokeWidth={2.2} /></button>
+          <button type="button" className="trip-action-btn" aria-label={archiveLabel} title={archiveLabel} onClick={(e) => stop(e, onArchive)}>{trip.is_archived ? <ArchiveRestore size={17} strokeWidth={2.2} /> : <Archive size={17} strokeWidth={2.2} />}</button>
+          <button type="button" className="trip-action-btn" aria-label={t('common.delete')} title={t('common.delete')} onClick={(e) => stop(e, onDelete)}><Trash2 size={17} strokeWidth={2.2} /></button>
         </div>
         <div className="trip-cover-content">
           <h3 className="trip-name">{trip.title}</h3>
@@ -636,7 +636,7 @@ function CurrencyTool(): React.ReactElement {
   const currencies = rates ? Object.keys(rates).sort() : CURRENCIES
   const ccyOptions = currencies.map(c => ({ value: c, label: c }))
   const rate = rates?.[to] ?? null
-  const converted = rate != null ? (parseFloat(amount.replace(',', '.')) || 0) * rate : null
+  const converted = rate != null ? (Number.parseFloat(amount.replace(',', '.')) || 0) * rate : null
 
   const swap = () => { setFrom(to); setTo(from) }
 
@@ -644,7 +644,7 @@ function CurrencyTool(): React.ReactElement {
     <div className="tool">
       <div className="tool-head">
         <div className="tool-title"><RefreshCw size={14} /> {t('dashboard.currency')}</div>
-        <button className="tool-action" aria-label={t('dashboard.aria.refreshRates')} onClick={fetchRate}><RefreshCw size={14} /></button>
+        <button type="button" className="tool-action" aria-label={t('dashboard.aria.refreshRates')} onClick={fetchRate}><RefreshCw size={14} /></button>
       </div>
       <div className="fx-input">
         <div className="fx-field">
@@ -652,7 +652,7 @@ function CurrencyTool(): React.ReactElement {
           <input className="amt mono" value={amount} onChange={e => setAmount(e.target.value)} inputMode="decimal" />
           <CustomSelect value={from} onChange={v => setFrom(String(v))} options={ccyOptions} searchable size="sm" style={{ marginTop: 6 }} />
         </div>
-        <button className="fx-swap" aria-label={t('dashboard.aria.swapCurrencies')} onClick={swap}><ArrowRightLeft size={14} /></button>
+        <button type="button" className="fx-swap" aria-label={t('dashboard.aria.swapCurrencies')} onClick={swap}><ArrowRightLeft size={14} /></button>
         <div className="fx-field">
           <div className="lbl">{t('dashboard.fx.to')}</div>
           <input className="amt mono" value={converted != null ? converted.toFixed(2) : '—'} readOnly />
@@ -739,7 +739,7 @@ function TimezoneTool({ locale }: { locale: string }): React.ReactElement {
     <div className="tool">
       <div className="tool-head">
         <div className="tool-title"><Clock size={14} /> {t('dashboard.timezone')}</div>
-        <button className="tool-action" aria-label={t('dashboard.aria.addTimezone')} onClick={() => setAdding(a => !a)}>
+        <button type="button" className="tool-action" aria-label={t('dashboard.aria.addTimezone')} onClick={() => setAdding(a => !a)}>
           {adding ? <X size={14} /> : <Plus size={14} />}
         </button>
       </div>
@@ -757,7 +757,7 @@ function TimezoneTool({ locale }: { locale: string }): React.ReactElement {
               <div className="tz-sub">{offsetLabel(tz)}</div>
             </div>
             <div className="tz-time mono">{timeIn(tz)}</div>
-            <button className="tz-del" aria-label={t('dashboard.aria.removeTimezone', { city: shortZone(tz) })} onClick={() => removeZone(tz)}><X size={13} /></button>
+            <button type="button" className="tz-del" aria-label={t('dashboard.aria.removeTimezone', { city: shortZone(tz) })} onClick={() => removeZone(tz)}><X size={13} /></button>
           </div>
         ))}
         {zones.length === 0 && (
diff --git a/client/src/pages/HelpPage.tsx b/client/src/pages/HelpPage.tsx
index 12018ebab..4d5902178 100644
--- a/client/src/pages/HelpPage.tsx
+++ b/client/src/pages/HelpPage.tsx
@@ -72,7 +72,7 @@ export default function HelpPage() {
         {/* Content */}
         <main className="flex-1 min-w-0" ref={contentRef}>
           {/* Mobile nav toggle */}
-          <button
+          <button type="button"
             onClick={() => setNavOpen(true)}
             className="lg:hidden inline-flex items-center gap-2 mb-4 px-3 py-2 rounded-lg bg-surface-card border border-edge text-[13px] font-medium text-content"
           >
@@ -109,7 +109,7 @@ export default function HelpPage() {
               <span className="text-[14px] font-bold text-content flex items-center gap-2">
                 <BookOpen size={16} className="text-accent" /> {t('help.title')}
               </span>
-              <button onClick={() => setNavOpen(false)} className="text-content-faint">
+              <button type="button" onClick={() => setNavOpen(false)} className="text-content-faint">
                 <X size={18} />
               </button>
             </div>
diff --git a/client/src/pages/InAppNotificationsPage.tsx b/client/src/pages/InAppNotificationsPage.tsx
index ea66e3886..a34c3a706 100644
--- a/client/src/pages/InAppNotificationsPage.tsx
+++ b/client/src/pages/InAppNotificationsPage.tsx
@@ -44,7 +44,7 @@ function InAppNotificationsPageDesktop(): React.ReactElement {
             {/* Bulk actions */}
             <div className="flex items-center gap-2">
               {unreadCount > 0 && (
-                <button
+                <button type="button"
                   onClick={markAllRead}
                   className="flex items-center gap-1.5 px-3 py-1.5 rounded-lg text-sm transition-colors text-content-secondary bg-surface-hover"
                   onMouseEnter={e => e.currentTarget.style.background = 'var(--bg-tertiary)'}
@@ -55,7 +55,7 @@ function InAppNotificationsPageDesktop(): React.ReactElement {
                 </button>
               )}
               {notifications.length > 0 && (
-                <button
+                <button type="button"
                   onClick={deleteAll}
                   className="flex items-center gap-1.5 px-3 py-1.5 rounded-lg text-sm transition-colors text-red-500 hover:bg-red-500/10"
                 >
@@ -68,13 +68,13 @@ function InAppNotificationsPageDesktop(): React.ReactElement {
 
           {/* Filter toggle */}
           <div className="flex gap-2 mb-4">
-            <button
+            <button type="button"
               onClick={() => setUnreadOnly(false)}
               className={`px-3 py-1.5 rounded-lg text-sm font-medium transition-colors ${!unreadOnly ? 'bg-content text-surface' : 'bg-surface-hover text-content-secondary'}`}
             >
               {t('notifications.all')}
             </button>
-            <button
+            <button type="button"
               onClick={() => setUnreadOnly(true)}
               className={`px-3 py-1.5 rounded-lg text-sm font-medium transition-colors ${unreadOnly ? 'bg-content text-surface' : 'bg-surface-hover text-content-secondary'}`}
             >
diff --git a/client/src/pages/JoinTripPage.tsx b/client/src/pages/JoinTripPage.tsx
index eeb2d50a6..ee06f4a25 100644
--- a/client/src/pages/JoinTripPage.tsx
+++ b/client/src/pages/JoinTripPage.tsx
@@ -34,7 +34,7 @@ export default function JoinTripPage() {
           <>
             <h1 style={{ fontSize: 18, fontWeight: 700, marginBottom: 8 }}>{t('trip.invite.invalidTitle')}</h1>
             <p className="text-content-secondary" style={{ fontSize: 14, marginBottom: 20 }}>{t('trip.invite.invalid')}</p>
-            <button
+            <button type="button"
               onClick={goToDashboard}
               className="bg-surface-hover text-content"
               style={{ border: 'none', borderRadius: 10, padding: '10px 18px', fontWeight: 600, cursor: 'pointer', fontFamily: 'inherit' }}
@@ -49,14 +49,14 @@ export default function JoinTripPage() {
               {state === 'loading' ? t('common.loading') : t('trip.invite.joinPrompt', { title })}
             </p>
             <div style={{ display: 'flex', gap: 10, justifyContent: 'center' }}>
-              <button
+              <button type="button"
                 onClick={goToDashboard}
                 className="bg-surface-hover text-content"
                 style={{ border: 'none', borderRadius: 10, padding: '10px 18px', fontWeight: 600, cursor: 'pointer', fontFamily: 'inherit' }}
               >
                 {t('common.cancel')}
               </button>
-              <button
+              <button type="button"
                 onClick={accept}
                 disabled={state !== 'ready'}
                 className="bg-accent text-accent-text"
diff --git a/client/src/pages/JourneyDetailPage.tsx b/client/src/pages/JourneyDetailPage.tsx
index 2feea2258..f326b02f0 100644
--- a/client/src/pages/JourneyDetailPage.tsx
+++ b/client/src/pages/JourneyDetailPage.tsx
@@ -126,7 +126,7 @@ function JourneyDetailPageDesktop() {
           className="fixed left-0 right-0 z-30 flex items-start justify-between gap-2 px-4"
           style={{ top: 'calc(var(--nav-h, 56px) + 12px)' }}
         >
-          <button
+          <button type="button"
             onClick={() => navigate('/journey')}
             aria-label={t('journey.detail.backToJourney')}
             className={barButton}
@@ -136,7 +136,7 @@ function JourneyDetailPageDesktop() {
 
           <div className="flex-1 min-w-0 flex justify-center">
             <div className="flex bg-surface-elevated backdrop-blur-lg border border-edge rounded-lg overflow-hidden shadow-lg">
-              <button
+              <button type="button"
                 onClick={() => setView('timeline')}
                 className={`flex items-center gap-1.5 px-3 py-[7px] text-[12px] font-medium ${
                   view === 'timeline'
@@ -147,7 +147,7 @@ function JourneyDetailPageDesktop() {
                 <MapPin size={13} />
                 {t('journey.detail.journeyTab') || 'Journey'}
               </button>
-              <button
+              <button type="button"
                 onClick={() => setView('gallery')}
                 className={`flex items-center gap-1.5 px-3 py-[7px] text-[12px] font-medium ${
                   view === 'gallery'
@@ -162,7 +162,7 @@ function JourneyDetailPageDesktop() {
           </div>
 
           <div className="flex items-center gap-1.5">
-            <button
+            <button type="button"
               onClick={openStudio}
               onMouseEnter={prefetchStudio}
               aria-label={t('journey.studio.openAria')}
@@ -170,7 +170,7 @@ function JourneyDetailPageDesktop() {
             >
               <BookOpen size={16} />
             </button>
-            <button
+            <button type="button"
               onClick={toggleSkeletons}
               aria-label={skeletonLabel}
               className={`${barButton} ${hideSkeletons ? 'bg-surface-selected' : ''}`}
@@ -178,7 +178,7 @@ function JourneyDetailPageDesktop() {
               {hideSkeletons ? <EyeOff size={16} /> : <Eye size={16} />}
             </button>
             {canEditJourney && (
-              <button
+              <button type="button"
                 onClick={() => setShowSettings(true)}
                 aria-label={t('journey.settings.title')}
                 className={barButton}
@@ -230,7 +230,7 @@ function JourneyDetailPageDesktop() {
 
                 <div className="relative z-[3] flex items-center justify-between mb-5">
                   <div className="flex items-center gap-2">
-                    <button
+                    <button type="button"
                       onClick={() => navigate('/journey')}
                       aria-label={t('journey.detail.backToJourney')}
                       className="w-[34px] h-[34px] rounded-full bg-white/15 backdrop-blur flex items-center justify-center hover:bg-white/25"
@@ -252,7 +252,7 @@ function JourneyDetailPageDesktop() {
                     </div>
                   </div>
                   <div className="flex items-center gap-1.5">
-                    <button
+                    <button type="button"
                       onClick={openStudio}
                       onMouseEnter={prefetchStudio}
                       className="inline-flex h-[34px] items-center gap-1.5 px-3.5 rounded-full bg-white/15 backdrop-blur border border-white/15 text-[12px] font-semibold hover:bg-white/25"
@@ -261,7 +261,7 @@ function JourneyDetailPageDesktop() {
                       {t('journey.studio.open')}
                     </button>
                     <div className="relative group">
-                      <button
+                      <button type="button"
                         onClick={toggleSkeletons}
                         aria-label={skeletonLabel}
                         className={`w-[34px] h-[34px] rounded-full backdrop-blur flex items-center justify-center ${hideSkeletons ? 'bg-white/30' : 'bg-white/15 hover:bg-white/25'}`}
@@ -273,7 +273,7 @@ function JourneyDetailPageDesktop() {
                       </span>
                     </div>
                     {canEditJourney && (
-                      <button onClick={() => setShowSettings(true)} aria-label={t('journey.settings.title')} className="w-[34px] h-[34px] rounded-full bg-white/15 backdrop-blur flex items-center justify-center hover:bg-white/25"><MoreHorizontal size={14} /></button>
+                      <button type="button" onClick={() => setShowSettings(true)} aria-label={t('journey.settings.title')} className="w-[34px] h-[34px] rounded-full bg-white/15 backdrop-blur flex items-center justify-center hover:bg-white/25"><MoreHorizontal size={14} /></button>
                     )}
                   </div>
                 </div>
@@ -320,7 +320,7 @@ function JourneyDetailPageDesktop() {
                         { id: 'gallery' as const, icon: Grid, label: t('journey.share.gallery') },
                       ]
                   ).map(v => (
-                    <button
+                    <button type="button"
                       key={v.id}
                       onClick={() => setView(v.id)}
                       className="flex items-center gap-1.5 px-3.5 py-[6px] text-[12px] font-semibold rounded-full transition-colors"
@@ -334,7 +334,7 @@ function JourneyDetailPageDesktop() {
                   ))}
                 </div>
                 {canEditEntries && view === 'timeline' && (
-                  <button
+                  <button type="button"
                     onClick={() => {
                       setEditingEntry(createDraftJourneyEntry(current.id))
                     }}
@@ -346,7 +346,7 @@ function JourneyDetailPageDesktop() {
                   </button>
                 )}
                 {canEditEntries && view === 'gallery' && (
-                  <button
+                  <button type="button"
                     onClick={() => galleryUploadRef.current?.()}
                     className="inline-flex items-center gap-1.5 h-9 px-4 rounded-full text-[13px] font-semibold transition-transform hover:-translate-y-0.5"
                     style={{ background: 'var(--vg-ink)', color: 'var(--vg-bg)' }}
@@ -472,7 +472,7 @@ function JourneyDetailPageDesktop() {
                 <div className="sticky bottom-0 z-20 h-0 pointer-events-none">
                   <div className="absolute bottom-6 left-1/2 -translate-x-1/2 flex gap-1.5 pointer-events-auto">
                     {!feedEdge.atTop && (
-                      <button
+                      <button type="button"
                         onClick={() => scrollFeedTo('top')}
                         aria-label={t('journey.detail.jumpToTop')}
                         title={t('journey.detail.jumpToTop')}
@@ -483,7 +483,7 @@ function JourneyDetailPageDesktop() {
                       </button>
                     )}
                     {!feedEdge.atBottom && (
-                      <button
+                      <button type="button"
                         onClick={() => scrollFeedTo('bottom')}
                         aria-label={t('journey.detail.jumpToLast')}
                         title={t('journey.detail.jumpToLast')}
diff --git a/client/src/pages/JourneyPage.tsx b/client/src/pages/JourneyPage.tsx
index e2e5b70db..0f12d8fee 100644
--- a/client/src/pages/JourneyPage.tsx
+++ b/client/src/pages/JourneyPage.tsx
@@ -48,7 +48,7 @@ function JourneyPageDesktop() {
           {/* Header — mobile */}
           <div className="md:hidden px-5 pt-5 pb-4 flex flex-col gap-2">
             <div className="flex items-center gap-2">
-              <button
+              <button type="button"
                 onClick={() => {
                   if (searchOpen) {
                     setSearchOpen(false)
@@ -62,7 +62,7 @@ function JourneyPageDesktop() {
               >
                 {searchOpen ? <X size={15} /> : <Search size={15} />}
               </button>
-              <button
+              <button type="button"
                 onClick={() => openCreateModal()}
                 className="flex-1 flex items-center justify-center gap-2 py-2.5 rounded-xl bg-zinc-900 dark:bg-white text-white dark:text-zinc-900 text-[14px] font-semibold active:scale-[0.98] transition-transform"
               >
@@ -102,13 +102,13 @@ function JourneyPageDesktop() {
                     </div>
                   </div>
                   <div className="flex items-center gap-2 flex-shrink-0">
-                    <button
+                    <button type="button"
                       onClick={() => setDismissedSuggestions(prev => new Set([...prev, activeSuggestion.id]))}
                       className="px-3 py-1.5 rounded-lg bg-white/10 border border-white/20 text-[12px] font-medium text-white hover:bg-white/20"
                     >
                       {t('journey.frontpage.dismiss')}
                     </button>
-                    <button
+                    <button type="button"
                       onClick={() => openCreateModal(activeSuggestion.id)}
                       className="px-3 py-1.5 rounded-lg !bg-white !text-zinc-900 text-[12px] font-medium hover:!bg-zinc-100"
                     >
@@ -221,7 +221,7 @@ function JourneyPageDesktop() {
                 ))}
 
                 {/* Create card */}
-                <button
+                <button type="button"
                   onClick={() => openCreateModal()}
                   className="group min-h-[200px] rounded-[24px] flex flex-col items-center justify-center gap-3 transition-transform duration-200 ease-[cubic-bezier(0.23,1,0.32,1)] cursor-pointer hover:-translate-y-1"
                   style={{ border: '1.5px dashed var(--vg-line2)', background: 'var(--vg-surf2)' }}
@@ -335,13 +335,13 @@ function JourneyPageDesktop() {
                 {selectedTripIds.size > 0 && <> · <strong className="text-zinc-900 dark:text-white">{totalPlaces}</strong> <span className="hidden md:inline">{t('journey.frontpage.placesImported')}</span><span className="md:hidden">{t('journey.frontpage.places')}</span></>}
               </div>
               <div className="flex items-center gap-2">
-                <button
+                <button type="button"
                   onClick={() => setShowCreate(false)}
                   className="px-3.5 py-2 rounded-lg border border-zinc-200 dark:border-zinc-600 text-[13px] font-medium text-zinc-700 dark:text-zinc-300 hover:bg-zinc-100 dark:hover:bg-zinc-700"
                 >
                   {t('common.cancel')}
                 </button>
-                <button
+                <button type="button"
                   onClick={handleCreate}
                   disabled={!newTitle.trim()}
                   className="px-3.5 py-2 rounded-lg bg-zinc-900 dark:bg-white text-white dark:text-zinc-900 text-[13px] font-medium hover:bg-zinc-800 dark:hover:bg-zinc-100 disabled:opacity-40 disabled:cursor-not-allowed"
diff --git a/client/src/pages/JourneyPublicPage.tsx b/client/src/pages/JourneyPublicPage.tsx
index e75a976ec..76e11a02f 100644
--- a/client/src/pages/JourneyPublicPage.tsx
+++ b/client/src/pages/JourneyPublicPage.tsx
@@ -496,7 +496,7 @@ export default function JourneyPublicPage() {
     views.length > 1 && (
       <div className="mb-6 flex w-fit overflow-hidden rounded-lg border border-zinc-200 bg-white dark:border-zinc-700 dark:bg-zinc-800">
         {views.map((v) => (
-          <button
+          <button type="button"
             key={v.id}
             onClick={() => setView(v.id)}
             className={`flex items-center gap-1.5 px-3 py-[7px] text-[12px] font-medium ${
@@ -560,7 +560,7 @@ export default function JourneyPublicPage() {
 
         {/* Language picker */}
         <div style={{ position: 'absolute', top: 12, right: 12, zIndex: 10 }}>
-          <button
+          <button type="button"
             onClick={() => setShowLangPicker((v) => !v)}
             style={{
               padding: '5px 12px',
@@ -802,7 +802,7 @@ export default function JourneyPublicPage() {
             >
               <div className="flex overflow-hidden rounded-lg border border-zinc-200 bg-white/90 shadow-lg backdrop-blur-lg dark:border-zinc-700 dark:bg-zinc-800/90">
                 {availableViews.map((v) => (
-                  <button
+                  <button type="button"
                     key={v.id}
                     onClick={() => setView(v.id)}
                     className={`flex items-center gap-1.5 px-3 py-[7px] text-[12px] font-medium ${
diff --git a/client/src/pages/LoginPage.tsx b/client/src/pages/LoginPage.tsx
index 453f8f1b5..75dd09970 100644
--- a/client/src/pages/LoginPage.tsx
+++ b/client/src/pages/LoginPage.tsx
@@ -223,7 +223,7 @@ export default function LoginPage(): React.ReactElement {
     <div style={{ minHeight: '100vh', display: 'flex', fontFamily: 'var(--font-system)', position: 'relative' }}>
       {/* Language dropdown */}
       <div style={{ position: 'absolute', top: 16, right: 16, zIndex: 10 }}>
-        <button
+        <button type="button"
           onClick={(e) => {
             e.stopPropagation();
             setLangDropdownOpen((o) => !o);
@@ -281,7 +281,7 @@ export default function LoginPage(): React.ReactElement {
             }}
           >
             {SUPPORTED_LANGUAGES.map(({ value, label }) => (
-              <button
+              <button type="button"
                 key={value}
                 role="option"
                 aria-selected={value === language}
@@ -1049,7 +1049,7 @@ export default function LoginPage(): React.ReactElement {
                     }}
                   >
                     {mode === 'login' ? t('login.noAccount') + ' ' : t('login.hasAccount') + ' '}
-                    <button
+                    <button type="button"
                       onClick={() => {
                         setMode((m) => (m === 'login' ? 'register' : 'login'));
                         setError('');
@@ -1185,7 +1185,7 @@ export default function LoginPage(): React.ReactElement {
 
           {/* Demo login button */}
           {appConfig?.demo_mode && (
-            <button
+            <button type="button"
               onClick={handleDemoLogin}
               disabled={isLoading}
               style={{
diff --git a/client/src/pages/OAuthAuthorizePage.tsx b/client/src/pages/OAuthAuthorizePage.tsx
index 9f4e7a133..158bba85c 100644
--- a/client/src/pages/OAuthAuthorizePage.tsx
+++ b/client/src/pages/OAuthAuthorizePage.tsx
@@ -50,7 +50,7 @@ export default function OAuthAuthorizePage(): React.ReactElement {
                 {t('oauth.authorize.loginDescription', { client: validation?.client?.name || clientId })}
               </p>
             </div>
-            <button
+            <button type="button"
                 onClick={handleLoginRedirect}
                 className="w-full flex items-center justify-center gap-2 px-4 py-2.5 rounded-lg text-sm font-medium text-white"
                 style={{ background: 'var(--accent-primary, #4f46e5)' }}>
@@ -88,7 +88,7 @@ export default function OAuthAuthorizePage(): React.ReactElement {
               <p className="text-xs mb-3" style={{ color: 'var(--text-tertiary)' }}>
                 {t('oauth.authorize.trustNote')}
               </p>
-              <button
+              <button type="button"
                   onClick={() => submitConsent(true)}
                   disabled={submitting || (validation?.scopeSelectable === true && selectedScopes.length === 0)}
                   className="w-full px-4 py-2.5 rounded-lg text-sm font-medium text-white disabled:opacity-60 transition-opacity"
@@ -106,7 +106,7 @@ export default function OAuthAuthorizePage(): React.ReactElement {
                             )
                             : t('oauth.authorize.approveAccess')}
               </button>
-              <button
+              <button type="button"
                   onClick={() => submitConsent(false)}
                   disabled={submitting}
                   className="w-full px-4 py-2.5 rounded-lg text-sm font-medium border transition-colors hover:bg-slate-50 dark:hover:bg-slate-800 disabled:opacity-60"
diff --git a/client/src/pages/SharedTripPage.tsx b/client/src/pages/SharedTripPage.tsx
index 6c8cbf235..319256acf 100644
--- a/client/src/pages/SharedTripPage.tsx
+++ b/client/src/pages/SharedTripPage.tsx
@@ -327,7 +327,7 @@ export default function SharedTripPage() {
 
         {/* Language picker - top right */}
         <div style={{ position: 'absolute', top: 12, right: 12, zIndex: 10 }}>
-          <button
+          <button type="button"
             onClick={() => setShowLangPicker((v) => !v)}
             className="bg-[rgba(255,255,255,0.1)] text-[rgba(255,255,255,0.7)]"
             style={{
@@ -400,7 +400,7 @@ export default function SharedTripPage() {
             ...(permissions?.share_budget ? [{ id: 'budget', label: t('shared.tabBudget'), Icon: Wallet }] : []),
             ...(permissions?.share_collab ? [{ id: 'collab', label: t('shared.tabChat'), Icon: MessageCircle }] : []),
           ].map((tab) => (
-            <button
+            <button type="button"
               key={tab.id}
               onClick={() => setActiveTab(tab.id)}
               className={activeTab === tab.id ? 'bg-[#111827] text-white' : 'bg-surface-card text-[#6b7280]'}
@@ -1022,7 +1022,7 @@ export default function SharedTripPage() {
               return g;
             }, {});
             const sumIn = (items: any[]) =>
-              items.reduce((s: number, i: any) => s + convert(parseFloat(i.total_price) || 0, curOf(i)), 0);
+              items.reduce((s: number, i: any) => s + convert(Number.parseFloat(i.total_price) || 0, curOf(i)), 0);
             const total = sumIn(budget || []);
             return (
               <div style={{ display: 'flex', flexDirection: 'column', gap: 12 }}>
diff --git a/client/src/pages/TripPlannerPage.tsx b/client/src/pages/TripPlannerPage.tsx
index a78644845..241ab686d 100644
--- a/client/src/pages/TripPlannerPage.tsx
+++ b/client/src/pages/TripPlannerPage.tsx
@@ -130,7 +130,7 @@ function ListsContainer({ tripId, packingItems, todoItems }: { tripId: number; p
               const active = subTab === tab.id
               const Icon = tab.icon
               return (
-                <button key={tab.id} onClick={() => setSubTabPersist(tab.id)}
+                <button type="button" key={tab.id} onClick={() => setSubTabPersist(tab.id)}
                   className={active ? 'bg-surface-card text-content' : 'bg-transparent text-content-muted'}
                   style={{
                     appearance: 'none', border: 'none', cursor: 'pointer', fontFamily: 'inherit',
@@ -162,7 +162,7 @@ function ListsContainer({ tripId, packingItems, todoItems }: { tripId: number; p
             return (
               <div style={{ display: 'flex', gap: 6, flexShrink: 0, marginLeft: 'auto', flexWrap: 'wrap' }}>
                 {packingAbgehakt > 0 && (
-                  <button onClick={() => setClearCheckedSignal(s => s + 1)}
+                  <button type="button" onClick={() => setClearCheckedSignal(s => s + 1)}
                     className={`hidden sm:inline-flex items-center gap-1.5 px-[14px] py-[9px] hover:opacity-[0.88] bg-[rgba(239,68,68,0.14)] text-[#ef4444]`}
                     style={sharedBtnStyle}
                   >
@@ -177,7 +177,7 @@ function ListsContainer({ tripId, packingItems, todoItems }: { tripId: number; p
                   style={sharedBtnStyle}
                 />
                 {isAdmin && packingItems.length > 0 && (
-                  <button onClick={() => setSaveTemplateSignal(s => s + 1)}
+                  <button type="button" onClick={() => setSaveTemplateSignal(s => s + 1)}
                     className={`${sharedBtnClass} bg-accent text-accent-text`}
                     style={sharedBtnStyle}
                   >
@@ -185,7 +185,7 @@ function ListsContainer({ tripId, packingItems, todoItems }: { tripId: number; p
                     <span className="hidden sm:inline">{t('packing.saveAsTemplate')}</span>
                   </button>
                 )}
-                <button onClick={() => setImportPackingSignal(s => s + 1)}
+                <button type="button" onClick={() => setImportPackingSignal(s => s + 1)}
                   className={`${sharedBtnClass} bg-accent text-accent-text`}
                   style={sharedBtnStyle}
                 >
@@ -196,7 +196,7 @@ function ListsContainer({ tripId, packingItems, todoItems }: { tripId: number; p
             )
           })()}
           {subTab === 'todo' && (
-            <button onClick={() => setAddTodoSignal(s => s + 1)}
+            <button type="button" onClick={() => setAddTodoSignal(s => s + 1)}
               className="hover:opacity-[0.88] bg-accent text-accent-text"
               style={{
                 appearance: 'none', border: 'none', cursor: 'pointer', fontFamily: 'inherit',
@@ -424,7 +424,7 @@ function TripPlannerPageDesktop(): React.ReactElement | null {
             )}
 
             <div className="hidden md:block" style={{ position: 'absolute', left: 10, top: 10, bottom: 10, zIndex: 20 }}>
-              <button onClick={() => setLeftCollapsed(c => !c)}
+              <button type="button" onClick={() => setLeftCollapsed(c => !c)}
                 style={{
                   position: leftCollapsed ? 'fixed' : 'absolute', top: leftCollapsed ? 'calc(var(--nav-h) + 44px + 14px)' : 14, left: leftCollapsed ? 10 : undefined, right: leftCollapsed ? undefined : -28, zIndex: -1,
                   width: 36, height: 36, borderRadius: leftCollapsed ? 10 : '0 10px 10px 0',
@@ -512,7 +512,7 @@ function TripPlannerPageDesktop(): React.ReactElement | null {
             </div>
 
             <div className="hidden md:block" style={{ position: 'absolute', right: 10, top: 10, bottom: 10, zIndex: 20 }}>
-              <button onClick={() => setRightCollapsed(c => !c)}
+              <button type="button" onClick={() => setRightCollapsed(c => !c)}
                 style={{
                   position: rightCollapsed ? 'fixed' : 'absolute', top: rightCollapsed ? 'calc(var(--nav-h) + 44px + 14px)' : 14, right: rightCollapsed ? 10 : undefined, left: rightCollapsed ? undefined : -28, zIndex: -1,
                   width: 36, height: 36, borderRadius: rightCollapsed ? 10 : '10px 0 0 10px',
@@ -571,12 +571,12 @@ function TripPlannerPageDesktop(): React.ReactElement | null {
             {/* Mobile sidebar buttons — portal to body to escape Leaflet touch handling */}
             {activeTab === 'plan' && !mobileSidebarOpen && !showPlaceForm && !showMembersModal && !showReservationModal && createPortal(
               <div className="flex md:hidden" style={{ position: 'fixed', top: 'calc(var(--nav-h) + 44px + 12px)', left: 12, right: 12, justifyContent: 'space-between', zIndex: 100, pointerEvents: 'none' }}>
-                <button onClick={() => setMobileSidebarOpen('left')}
+                <button type="button" onClick={() => setMobileSidebarOpen('left')}
                   className="bg-surface-card text-content border border-edge"
                   style={{ pointerEvents: 'auto', backdropFilter: 'blur(12px)', borderRadius: 24, padding: '11px 24px', fontSize: 'calc(15px * var(--fs-scale-subtitle, 1))', fontWeight: 600, cursor: 'pointer', boxShadow: '0 2px 12px rgba(0,0,0,0.15)', minHeight: 44, fontFamily: 'inherit', touchAction: 'manipulation' }}>
                   {t('trip.mobilePlan')}
                 </button>
-                <button onClick={() => setMobileSidebarOpen('right')}
+                <button type="button" onClick={() => setMobileSidebarOpen('right')}
                   className="bg-surface-card text-content border border-edge"
                   style={{ pointerEvents: 'auto', backdropFilter: 'blur(12px)', borderRadius: 24, padding: '11px 24px', fontSize: 'calc(15px * var(--fs-scale-subtitle, 1))', fontWeight: 600, cursor: 'pointer', boxShadow: '0 2px 12px rgba(0,0,0,0.15)', minHeight: 44, fontFamily: 'inherit', touchAction: 'manipulation' }}>
                   {t('trip.mobilePlaces')}
@@ -702,7 +702,7 @@ function TripPlannerPageDesktop(): React.ReactElement | null {
                 <div className="bg-surface-card" style={{ position: 'absolute', top: 'var(--nav-h)', left: 0, right: 0, bottom: 0, display: 'flex', flexDirection: 'column', overflow: 'hidden' }} onClick={e => e.stopPropagation()}>
                   <div className="border-b border-edge-secondary" style={{ display: 'flex', alignItems: 'center', justifyContent: 'space-between', padding: '14px 16px' }}>
                     <span className="text-content" style={{ fontWeight: 600, fontSize: 'calc(14px * var(--fs-scale-body, 1))' }}>{mobileSidebarOpen === 'left' ? t('trip.mobilePlan') : t('trip.mobilePlaces')}</span>
-                    <button onClick={() => setMobileSidebarOpen(null)} className="bg-surface-tertiary text-content" style={{ border: 'none', borderRadius: '50%', width: 28, height: 28, cursor: 'pointer', display: 'flex', alignItems: 'center', justifyContent: 'center' }}>
+                    <button type="button" onClick={() => setMobileSidebarOpen(null)} className="bg-surface-tertiary text-content" style={{ border: 'none', borderRadius: '50%', width: 28, height: 28, cursor: 'pointer', display: 'flex', alignItems: 'center', justifyContent: 'center' }}>
                       <X size={14} />
                     </button>
                   </div>
diff --git a/client/src/pages/VacayPage.tsx b/client/src/pages/VacayPage.tsx
index 420d266ed..cbfa25860 100644
--- a/client/src/pages/VacayPage.tsx
+++ b/client/src/pages/VacayPage.tsx
@@ -48,19 +48,19 @@ function VacayPageDesktop(): React.ReactElement {
         </div>
         <div className="flex items-center justify-between mb-3">
           <div className="flex items-center gap-0.5">
-            <button onClick={handleAddPrevYear} className="w-7 h-7 rounded-lg flex items-center justify-center transition-colors" style={{ color: 'var(--vg-ink3)' }} title={t('vacay.addPrevYear')}>
+            <button type="button" onClick={handleAddPrevYear} className="w-7 h-7 rounded-lg flex items-center justify-center transition-colors" style={{ color: 'var(--vg-ink3)' }} title={t('vacay.addPrevYear')}>
               <Plus size={14} />
             </button>
-            <button onClick={() => { const idx = years.indexOf(selectedYear); if (idx > 0) setSelectedYear(years[idx - 1]) }} disabled={years.indexOf(selectedYear) <= 0} className="w-7 h-7 rounded-lg flex items-center justify-center disabled:opacity-20 transition-colors" style={{ color: 'var(--vg-ink3)' }}>
+            <button type="button" onClick={() => { const idx = years.indexOf(selectedYear); if (idx > 0) setSelectedYear(years[idx - 1]) }} disabled={years.indexOf(selectedYear) <= 0} className="w-7 h-7 rounded-lg flex items-center justify-center disabled:opacity-20 transition-colors" style={{ color: 'var(--vg-ink3)' }}>
               <ChevronLeft size={16} />
             </button>
           </div>
           <span className="tabular-nums" style={{ fontSize: 22, fontWeight: 700, color: 'var(--vg-ink)' }}>{selectedYear}</span>
           <div className="flex items-center gap-0.5">
-            <button onClick={() => { const idx = years.indexOf(selectedYear); if (idx < years.length - 1) setSelectedYear(years[idx + 1]) }} disabled={years.indexOf(selectedYear) >= years.length - 1} className="w-7 h-7 rounded-lg flex items-center justify-center disabled:opacity-20 transition-colors" style={{ color: 'var(--vg-ink3)' }}>
+            <button type="button" onClick={() => { const idx = years.indexOf(selectedYear); if (idx < years.length - 1) setSelectedYear(years[idx + 1]) }} disabled={years.indexOf(selectedYear) >= years.length - 1} className="w-7 h-7 rounded-lg flex items-center justify-center disabled:opacity-20 transition-colors" style={{ color: 'var(--vg-ink3)' }}>
               <ChevronRight size={16} />
             </button>
-            <button onClick={handleAddNextYear} className="w-7 h-7 rounded-lg flex items-center justify-center transition-colors" style={{ color: 'var(--vg-ink3)' }} title={t('vacay.addYear')}>
+            <button type="button" onClick={handleAddNextYear} className="w-7 h-7 rounded-lg flex items-center justify-center transition-colors" style={{ color: 'var(--vg-ink3)' }} title={t('vacay.addYear')}>
               <Plus size={14} />
             </button>
           </div>
@@ -129,13 +129,13 @@ function VacayPageDesktop(): React.ReactElement {
               <h1 className="text-lg font-bold text-content">{t('admin.addons.catalog.vacay.name')}</h1>
             </div>
             <div className="flex items-center gap-2">
-              <button
+              <button type="button"
                 onClick={() => setShowMobileSidebar(true)}
                 className="lg:hidden flex items-center gap-1.5 px-3 py-1.5 rounded-lg text-sm transition-colors bg-surface-secondary text-content-muted"
               >
                 <SlidersHorizontal size={14} />
               </button>
-              <button
+              <button type="button"
                 onClick={() => setShowSettings(true)}
                 className="flex items-center gap-1.5 px-3 py-1.5 rounded-lg text-sm transition-colors bg-surface-secondary text-content-muted"
               >
@@ -149,7 +149,7 @@ function VacayPageDesktop(): React.ReactElement {
             {/* Desktop Sidebar */}
             <div className="hidden lg:flex w-[300px] shrink-0 flex-col gap-[12px] sticky top-[84px]">
               {sidebarContent}
-              <button
+              <button type="button"
                 onClick={() => setShowSettings(true)}
                 className="vg-card flex items-center justify-center gap-2.5 rounded-[18px] transition-transform hover:-translate-y-px"
                 style={{ padding: '13px 16px', fontSize: 14, fontWeight: 600, color: 'var(--vg-ink)', cursor: 'pointer' }}
@@ -197,10 +197,10 @@ function VacayPageDesktop(): React.ReactElement {
             </div>
           </div>
           <div className="flex gap-3 justify-end">
-            <button onClick={() => setDeleteYear(null)} className="px-4 py-2 text-sm rounded-lg transition-colors border text-content-muted border-edge">
+            <button type="button" onClick={() => setDeleteYear(null)} className="px-4 py-2 text-sm rounded-lg transition-colors border text-content-muted border-edge">
               {t('common.cancel')}
             </button>
-            <button onClick={async () => { await removeYear(deleteYear); setDeleteYear(null) }} className="px-4 py-2 text-sm bg-red-500 hover:bg-red-600 text-white rounded-lg transition-colors">
+            <button type="button" onClick={async () => { await removeYear(deleteYear); setDeleteYear(null) }} className="px-4 py-2 text-sm bg-red-500 hover:bg-red-600 text-white rounded-lg transition-colors">
               {t('vacay.remove')}
             </button>
           </div>
@@ -232,11 +232,11 @@ function VacayPageDesktop(): React.ReactElement {
                 <InfoItem icon={Unlink} text={t('vacay.fuseInfo5')} />
               </div>
               <div className="px-6 pb-6 flex gap-3">
-                <button onClick={() => declineInvite(inv.plan_id)}
+                <button type="button" onClick={() => declineInvite(inv.plan_id)}
                   className="flex-1 px-4 py-2.5 text-sm font-medium rounded-xl transition-colors border text-content-muted border-edge">
                   {t('vacay.decline')}
                 </button>
-                <button onClick={() => acceptInvite(inv.plan_id)}
+                <button type="button" onClick={() => acceptInvite(inv.plan_id)}
                   className="flex-1 px-4 py-2.5 text-sm font-medium rounded-xl transition-colors bg-content text-surface-card">
                   {t('vacay.acceptFusion')}
                 </button>
diff --git a/client/src/pages/admin/AdminNotificationsPanel.tsx b/client/src/pages/admin/AdminNotificationsPanel.tsx
index d9173075f..a62072acd 100644
--- a/client/src/pages/admin/AdminNotificationsPanel.tsx
+++ b/client/src/pages/admin/AdminNotificationsPanel.tsx
@@ -93,7 +93,7 @@ export default function AdminNotificationsPanel({ t, toast }: { t: (k: string) =
                   const isOn = matrix.preferences[eventType]?.[ch] ?? true
                   return (
                     <div key={ch} style={{ display: 'flex', justifyContent: 'center' }}>
-                      <button
+                      <button type="button"
                         onClick={() => toggle(eventType, ch)}
                         className={`relative inline-flex h-5 w-9 items-center rounded-full transition-colors flex-shrink-0 ${isOn ? 'bg-content' : 'bg-edge'}`}
                       >
diff --git a/client/src/pages/admin/AdminNotificationsTab.tsx b/client/src/pages/admin/AdminNotificationsTab.tsx
index 370cf6cfd..7f7c18d7c 100644
--- a/client/src/pages/admin/AdminNotificationsTab.tsx
+++ b/client/src/pages/admin/AdminNotificationsTab.tsx
@@ -69,7 +69,7 @@ export default function AdminNotificationsTab({ admin, t }: AdminNotificationsTa
             <h2 className="font-semibold text-slate-900">{t('admin.notifications.emailPanel.title')}</h2>
             <p className="text-xs text-slate-400 mt-1">{t('admin.smtp.hint')}</p>
           </div>
-          <button
+          <button type="button"
             onClick={() => setChannels(!emailActive, webhookActive, ntfyActive)}
             className={`relative inline-flex h-6 w-11 items-center rounded-full transition-colors flex-shrink-0 ${emailActive ? 'bg-content' : 'bg-edge'}`}
           >
@@ -112,11 +112,11 @@ export default function AdminNotificationsTab({ admin, t }: AdminNotificationsTa
           </div>
         </div>
         <div className="px-6 pb-4 flex items-center gap-2 border-t border-slate-100 pt-4">
-          <button onClick={saveNotifications}
+          <button type="button" onClick={saveNotifications}
             className="flex items-center gap-2 px-4 py-2 bg-slate-900 text-white rounded-lg text-sm font-medium hover:bg-slate-800 transition-colors">
             <Save className="w-4 h-4" />{t('common.save')}
           </button>
-          <button
+          <button type="button"
             onClick={async () => {
               const smtpKeys = ['smtp_host', 'smtp_port', 'smtp_user', 'smtp_pass', 'smtp_from', 'smtp_skip_tls_verify']
               const payload: Record<string, string> = {}
@@ -144,7 +144,7 @@ export default function AdminNotificationsTab({ admin, t }: AdminNotificationsTa
             <h2 className="font-semibold text-slate-900">{t('admin.notifications.webhookPanel.title')}</h2>
             <p className="text-xs text-slate-400 mt-1">{t('admin.webhook.hint')}</p>
           </div>
-          <button
+          <button type="button"
             onClick={() => setChannels(emailActive, !webhookActive, ntfyActive)}
             className={`relative inline-flex h-6 w-11 items-center rounded-full transition-colors flex-shrink-0 ${webhookActive ? 'bg-content' : 'bg-edge'}`}
           >
@@ -161,7 +161,7 @@ export default function AdminNotificationsTab({ admin, t }: AdminNotificationsTa
             <h2 className="font-semibold text-slate-900">{t('admin.notifications.ntfy')}</h2>
             <p className="text-xs text-slate-400 mt-1">{t('admin.ntfy.hint') || 'Allow users to configure their own ntfy topics for push notifications.'}</p>
           </div>
-          <button
+          <button type="button"
             onClick={() => setChannels(emailActive, webhookActive, !ntfyActive)}
             className={`relative inline-flex h-6 w-11 items-center rounded-full transition-colors flex-shrink-0 ${ntfyActive ? 'bg-content' : 'bg-edge'}`}
           >
@@ -240,7 +240,7 @@ export default function AdminNotificationsTab({ admin, t }: AdminNotificationsTa
           )}
         </div>
         <div className="px-6 pb-4 flex items-center gap-2 border-t border-slate-100 pt-4">
-          <button
+          <button type="button"
             onClick={async () => {
               try {
                 await authApi.updateAppSettings({ admin_webhook_url: smtpValues.admin_webhook_url || '' })
@@ -250,7 +250,7 @@ export default function AdminNotificationsTab({ admin, t }: AdminNotificationsTa
             className="flex items-center gap-2 px-4 py-2 bg-slate-900 text-white rounded-lg text-sm font-medium hover:bg-slate-800 transition-colors">
             <Save className="w-4 h-4" />{t('common.save')}
           </button>
-          <button
+          <button type="button"
             onClick={async () => {
               // A masked value means the URL only lives on the server — send no url and let
               // the server test the stored one instead of pre-saving the mask.
@@ -331,7 +331,7 @@ export default function AdminNotificationsTab({ admin, t }: AdminNotificationsTa
           )}
         </div>
         <div className="px-6 pb-4 flex items-center gap-2 border-t border-slate-100 pt-4">
-          <button
+          <button type="button"
             onClick={async () => {
               try {
                 await authApi.updateAppSettings({
@@ -347,7 +347,7 @@ export default function AdminNotificationsTab({ admin, t }: AdminNotificationsTa
             className="flex items-center gap-2 px-4 py-2 bg-slate-900 text-white rounded-lg text-sm font-medium hover:bg-slate-800 transition-colors">
             <Save className="w-4 h-4" />{t('common.save')}
           </button>
-          <button
+          <button type="button"
             onClick={async () => {
               const topic = smtpValues.admin_ntfy_topic?.trim()
               if (!topic) return
diff --git a/client/src/pages/admin/AdminSettingsTab.tsx b/client/src/pages/admin/AdminSettingsTab.tsx
index b329881f9..95c04d3db 100644
--- a/client/src/pages/admin/AdminSettingsTab.tsx
+++ b/client/src/pages/admin/AdminSettingsTab.tsx
@@ -54,7 +54,7 @@ export default function AdminSettingsTab({ admin, t }: AdminSettingsTabProps): R
               <p className="text-sm font-medium text-slate-700">{t('admin.passwordLogin')}</p>
               <p className="text-xs text-slate-400 mt-0.5">{t('admin.passwordLoginHint')}</p>
             </div>
-            <button
+            <button type="button"
               disabled={envOverrideOidcOnly || (!passwordLogin && !oidcLogin)}
               onClick={() => handleToggleAuthSetting('password_login', !passwordLogin, setPasswordLogin)}
               title={!passwordLogin && !oidcLogin ? t('admin.lockoutWarning') : undefined}
@@ -72,7 +72,7 @@ export default function AdminSettingsTab({ admin, t }: AdminSettingsTabProps): R
               <p className="text-sm font-medium text-slate-700">{t('admin.passwordRegistration')}</p>
               <p className="text-xs text-slate-400 mt-0.5">{t('admin.passwordRegistrationHint')}</p>
             </div>
-            <button
+            <button type="button"
               disabled={envOverrideOidcOnly}
               onClick={() => handleToggleAuthSetting('password_registration', !passwordRegistration, setPasswordRegistration)}
               className={`relative inline-flex h-6 w-11 items-center rounded-full transition-colors disabled:opacity-50 ${passwordRegistration ? 'bg-content' : 'bg-edge'}`}
@@ -90,7 +90,7 @@ export default function AdminSettingsTab({ admin, t }: AdminSettingsTabProps): R
                 <p className="text-sm font-medium text-slate-700">{t('admin.oidcLogin')}</p>
                 <p className="text-xs text-slate-400 mt-0.5">{t('admin.oidcLoginHint')}</p>
               </div>
-              <button
+              <button type="button"
                 disabled={!passwordLogin && oidcLogin}
                 onClick={() => handleToggleAuthSetting('oidc_login', !oidcLogin, setOidcLogin)}
                 title={!passwordLogin && oidcLogin ? t('admin.lockoutWarning') : undefined}
@@ -110,7 +110,7 @@ export default function AdminSettingsTab({ admin, t }: AdminSettingsTabProps): R
                 <p className="text-sm font-medium text-slate-700">{t('admin.oidcRegistration')}</p>
                 <p className="text-xs text-slate-400 mt-0.5">{t('admin.oidcRegistrationHint')}</p>
               </div>
-              <button
+              <button type="button"
                 onClick={() => handleToggleAuthSetting('oidc_registration', !oidcRegistration, setOidcRegistration)}
                 className={`relative inline-flex h-6 w-11 flex-shrink-0 items-center rounded-full transition-colors ${oidcRegistration ? 'bg-content' : 'bg-edge'}`}
               >
@@ -237,7 +237,7 @@ export default function AdminSettingsTab({ admin, t }: AdminSettingsTabProps): R
             className="w-full px-3 py-2 border border-slate-300 rounded-lg text-sm focus:ring-2 focus:ring-slate-400 focus:border-transparent"
           />
           <p className="text-xs text-slate-400 mt-2">{t('admin.fileTypesFormat')}</p>
-          <button
+          <button type="button"
             onClick={async () => {
               setSavingFileTypes(true)
               try {
@@ -293,7 +293,7 @@ export default function AdminSettingsTab({ admin, t }: AdminSettingsTabProps): R
                   {showKeys.maps ? <EyeOff className="w-4 h-4" /> : <Eye className="w-4 h-4" />}
                 </button>
               </div>
-              <button
+              <button type="button"
                 onClick={() => handleValidateKey('maps')}
                 disabled={!mapsKey || validating.maps}
                 className="px-3 py-2 text-sm border border-slate-300 rounded-lg hover:bg-slate-50 disabled:opacity-40 disabled:cursor-not-allowed flex items-center gap-1.5"
@@ -451,7 +451,7 @@ export default function AdminSettingsTab({ admin, t }: AdminSettingsTabProps): R
             </div>
           </div>
 
-          <button
+          <button type="button"
             onClick={handleSaveApiKeys}
             disabled={savingKeys}
             className="flex items-center gap-2 px-4 py-2 bg-slate-900 text-white rounded-lg text-sm hover:bg-slate-700 disabled:bg-slate-400"
@@ -525,7 +525,7 @@ export default function AdminSettingsTab({ admin, t }: AdminSettingsTabProps): R
               className="w-full px-3 py-2 border border-slate-300 rounded-lg text-sm focus:ring-2 focus:ring-slate-400 focus:border-transparent"
             />
           </div>
-          <button
+          <button type="button"
             onClick={async () => {
               setSavingOidc(true)
               try {
@@ -565,7 +565,7 @@ export default function AdminSettingsTab({ admin, t }: AdminSettingsTabProps): R
               <p className="text-sm font-medium text-slate-700">Rotate JWT Secret</p>
               <p className="text-xs text-slate-400 mt-0.5">Generate a new JWT signing secret. All active sessions will be invalidated immediately.</p>
             </div>
-            <button
+            <button type="button"
               onClick={() => setShowRotateJwtModal(true)}
               className="flex items-center gap-2 px-4 py-2 bg-red-600 hover:bg-red-700 text-white rounded-lg text-sm font-medium transition-colors"
             >
diff --git a/client/src/pages/admin/AdminUpdateBanner.tsx b/client/src/pages/admin/AdminUpdateBanner.tsx
index 3ff022a1b..79c042d2c 100644
--- a/client/src/pages/admin/AdminUpdateBanner.tsx
+++ b/client/src/pages/admin/AdminUpdateBanner.tsx
@@ -37,7 +37,7 @@ export default function AdminUpdateBanner({ updateInfo, t, onHowTo }: AdminUpdat
             {t('admin.update.button')}
           </a>
         )}
-        <button
+        <button type="button"
           onClick={onHowTo}
           className="flex items-center gap-1.5 px-4 py-2 rounded-lg text-sm font-semibold transition-colors bg-slate-900 dark:bg-white text-white dark:text-slate-900 hover:bg-slate-700 dark:hover:bg-gray-200"
         >
diff --git a/client/src/pages/admin/AdminUserModals.tsx b/client/src/pages/admin/AdminUserModals.tsx
index d74b4bea1..005f1d4b0 100644
--- a/client/src/pages/admin/AdminUserModals.tsx
+++ b/client/src/pages/admin/AdminUserModals.tsx
@@ -58,13 +58,13 @@ export default function AdminUserModals({ admin, t }: AdminUserModalsProps): Rea
         size="sm"
         footer={
           <div className="flex justify-end gap-3">
-            <button
+            <button type="button"
               onClick={() => setShowCreateUser(false)}
               className="rounded-lg border border-slate-200 px-4 py-2 text-sm text-slate-600 hover:bg-slate-50"
             >
               {t('common.cancel')}
             </button>
-            <button
+            <button type="button"
               onClick={handleCreateUser}
               className="rounded-lg bg-slate-900 px-4 py-2 text-sm text-white hover:bg-slate-700"
             >
@@ -137,13 +137,13 @@ export default function AdminUserModals({ admin, t }: AdminUserModalsProps): Rea
         size="sm"
         footer={
           <div className="flex justify-end gap-3">
-            <button
+            <button type="button"
               onClick={() => setEditingUser(null)}
               className="rounded-lg border border-slate-200 px-4 py-2 text-sm text-slate-600 hover:bg-slate-50"
             >
               {t('common.cancel')}
             </button>
-            <button
+            <button type="button"
               onClick={handleSaveUser}
               className="rounded-lg bg-slate-900 px-4 py-2 text-sm text-white hover:bg-slate-700"
             >
@@ -392,7 +392,7 @@ docker run -d --name trek \\
             </div>
 
             <div style={{ padding: '0 24px 20px', display: 'flex', justifyContent: 'flex-end' }}>
-              <button
+              <button type="button"
                 onClick={() => setShowUpdateModal(false)}
                 className="bg-slate-900 text-white hover:bg-slate-700 dark:bg-white dark:text-slate-900 dark:hover:bg-gray-200"
                 style={{
@@ -420,14 +420,14 @@ docker run -d --name trek \\
         size="sm"
         footer={
           <div className="flex justify-end gap-3">
-            <button
+            <button type="button"
               onClick={() => setShowRotateJwtModal(false)}
               disabled={rotatingJwt}
               className="rounded-lg border border-slate-200 px-4 py-2 text-sm text-slate-600 hover:bg-slate-50 disabled:opacity-50"
             >
               {t('common.cancel')}
             </button>
-            <button
+            <button type="button"
               onClick={async () => {
                 setRotatingJwt(true);
                 try {
diff --git a/client/src/pages/admin/AdminUsersTab.tsx b/client/src/pages/admin/AdminUsersTab.tsx
index 1a81105a5..4e87419ae 100644
--- a/client/src/pages/admin/AdminUsersTab.tsx
+++ b/client/src/pages/admin/AdminUsersTab.tsx
@@ -32,7 +32,7 @@ export default function AdminUsersTab({ admin, t, locale }: AdminUsersTabProps):
             <h2 className="font-semibold text-slate-900">{t('admin.tabs.users')}</h2>
             <p className="text-xs text-slate-400 mt-1">{users.length} {t('admin.stats.users')}</p>
           </div>
-          <button
+          <button type="button"
             onClick={() => setShowCreateUser(true)}
             className="flex items-center gap-1.5 px-3 py-1.5 text-sm bg-slate-900 text-white rounded-lg hover:bg-slate-700 transition-colors"
           >
@@ -100,14 +100,14 @@ export default function AdminUsersTab({ admin, t, locale }: AdminUsersTabProps):
                     </td>
                     <td className="px-5 py-3">
                       <div className="flex items-center gap-2 justify-end">
-                        <button
+                        <button type="button"
                           onClick={() => handleEditUser(u)}
                           className="p-1.5 text-slate-400 hover:text-slate-900 hover:bg-slate-100 rounded-lg transition-colors"
                           title={t('admin.editUser')}
                         >
                           <Edit2 className="w-4 h-4" />
                         </button>
-                        <button
+                        <button type="button"
                           onClick={() => handleDeleteUser(u)}
                           disabled={u.id === currentUser?.id}
                           className="p-1.5 text-slate-400 hover:text-red-600 hover:bg-red-50 rounded-lg transition-colors disabled:opacity-30 disabled:cursor-not-allowed"
@@ -132,7 +132,7 @@ export default function AdminUsersTab({ admin, t, locale }: AdminUsersTabProps):
             <h2 className="font-semibold text-slate-900">{t('admin.invite.title')}</h2>
             <p className="text-xs text-slate-400 mt-1">{t('admin.invite.subtitle')}</p>
           </div>
-          <button
+          <button type="button"
             onClick={() => setShowCreateInvite(true)}
             className="flex items-center gap-1.5 px-3 py-1.5 text-sm bg-slate-900 text-white rounded-lg hover:bg-slate-700 transition-colors"
           >
@@ -169,12 +169,12 @@ export default function AdminUsersTab({ admin, t, locale }: AdminUsersTabProps):
                     </div>
                   </div>
                   {isActive && (
-                    <button onClick={() => copyInviteLink(inv.token)} title={t('admin.invite.copyLink')}
+                    <button type="button" onClick={() => copyInviteLink(inv.token)} title={t('admin.invite.copyLink')}
                       className="p-1.5 rounded-lg hover:bg-slate-100 text-slate-400 hover:text-slate-700 transition-colors">
                       <Copy className="w-3.5 h-3.5" />
                     </button>
                   )}
-                  <button onClick={() => handleDeleteInvite(inv.id)} title={t('common.delete')}
+                  <button type="button" onClick={() => handleDeleteInvite(inv.id)} title={t('common.delete')}
                     className="p-1.5 rounded-lg hover:bg-red-50 text-slate-400 hover:text-red-500 transition-colors">
                     <Trash2 className="w-3.5 h-3.5" />
                   </button>
@@ -239,8 +239,8 @@ export default function AdminUsersTab({ admin, t, locale }: AdminUsersTabProps):
             </div>
           )}
           <div className="flex justify-end gap-2 pt-2 border-t border-slate-100">
-            <button onClick={() => setShowCreateInvite(false)} className="px-4 py-2 text-sm text-slate-500 hover:text-slate-700">{t('common.cancel')}</button>
-            <button onClick={handleCreateInvite} className="px-4 py-2 text-sm bg-slate-900 text-white rounded-lg hover:bg-slate-700">{t('admin.invite.createAndCopy')}</button>
+            <button type="button" onClick={() => setShowCreateInvite(false)} className="px-4 py-2 text-sm text-slate-500 hover:text-slate-700">{t('common.cancel')}</button>
+            <button type="button" onClick={handleCreateInvite} className="px-4 py-2 text-sm bg-slate-900 text-white rounded-lg hover:bg-slate-700">{t('admin.invite.createAndCopy')}</button>
           </div>
         </div>
       </Modal>
diff --git a/client/src/pages/atlas/AtlasCountrySearch.tsx b/client/src/pages/atlas/AtlasCountrySearch.tsx
index 800a50bf4..4c7bd0855 100644
--- a/client/src/pages/atlas/AtlasCountrySearch.tsx
+++ b/client/src/pages/atlas/AtlasCountrySearch.tsx
@@ -113,7 +113,7 @@ export default function AtlasCountrySearch({
             }}
           />
           {search.trim() && (
-            <button
+            <button type="button"
               onClick={() => {
                 setSearch('')
                 setResults([])
@@ -142,7 +142,7 @@ export default function AtlasCountrySearch({
             }}
           >
             {results.map((r) => (
-              <button
+              <button type="button"
                 key={r.code}
                 onClick={() => onSelect(r.code)}
                 style={{
@@ -187,7 +187,7 @@ export default function AtlasCountrySearch({
               </div>
             )}
             {placeResults.map((p) => (
-              <button
+              <button type="button"
                 key={`${p.lat},${p.lng},${p.name}`}
                 onClick={() => onSelectPlace(p)}
                 style={{
diff --git a/client/src/pages/atlas/useAtlas.ts b/client/src/pages/atlas/useAtlas.ts
index d67ac283b..0e886545a 100644
--- a/client/src/pages/atlas/useAtlas.ts
+++ b/client/src/pages/atlas/useAtlas.ts
@@ -14,9 +14,9 @@ const PLANNED_KEY = 'trek_atlas_show_planned'
 
 function hexToRgba(hex: string, alpha: number): string {
   const clean = hex.replace('#', '')
-  const r = parseInt(clean.substring(0, 2), 16)
-  const g = parseInt(clean.substring(2, 4), 16)
-  const b = parseInt(clean.substring(4, 6), 16)
+  const r = Number.parseInt(clean.substring(0, 2), 16)
+  const g = Number.parseInt(clean.substring(2, 4), 16)
+  const b = Number.parseInt(clean.substring(4, 6), 16)
   return `rgba(${r},${g},${b},${alpha})`
 }
 
@@ -988,8 +988,8 @@ export function useAtlas() {
   const handleAddBucketItem = async (): Promise<void> => {
     if (!bucketForm.name.trim()) return
     const hasCoords = !!(bucketForm.lat && bucketForm.lng)
-    const lat = hasCoords ? parseFloat(bucketForm.lat) : null
-    const lng = hasCoords ? parseFloat(bucketForm.lng) : null
+    const lat = hasCoords ? Number.parseFloat(bucketForm.lat) : null
+    const lng = hasCoords ? Number.parseFloat(bucketForm.lng) : null
     const targetDate = bucketForm.target_date || (bucketPoiMonth > 0 && bucketPoiYear > 0 ? `${bucketPoiYear}-${String(bucketPoiMonth).padStart(2, '0')}` : null)
     // #1898: this form never sends a country code, so the entry it would create
     // is identified by name, date and coordinates alone. Keep the form filled so
diff --git a/client/src/pages/journeyDetail/JourneyDetailPage.helpers.ts b/client/src/pages/journeyDetail/JourneyDetailPage.helpers.ts
index a58e6463d..16ea5199e 100644
--- a/client/src/pages/journeyDetail/JourneyDetailPage.helpers.ts
+++ b/client/src/pages/journeyDetail/JourneyDetailPage.helpers.ts
@@ -126,7 +126,7 @@ export function sortProviderPhotos<T extends ProviderPhotoAsset>(photos: T[], lo
     .map((photo, index) => ({
       photo,
       index,
-      distance: isValidGeoPoint({ lat: photo.lat ?? NaN, lng: photo.lng ?? NaN })
+      distance: isValidGeoPoint({ lat: photo.lat ?? Number.NaN, lng: photo.lng ?? Number.NaN })
         ? distanceBetweenGeoPoints(location, { lat: photo.lat!, lng: photo.lng! })
         : null,
     }))
diff --git a/client/src/pages/journeyStudio/useJourneyStudio.ts b/client/src/pages/journeyStudio/useJourneyStudio.ts
index 38ddd841a..fe560577a 100644
--- a/client/src/pages/journeyStudio/useJourneyStudio.ts
+++ b/client/src/pages/journeyStudio/useJourneyStudio.ts
@@ -295,11 +295,11 @@ export function useJourneyStudio() {
      */
     const points = stats?.points ?? []
     const dayCount = stats?.days ?? null
-    const first = stats?.start ? Date.parse(`${stats.start}T00:00:00`) : NaN
+    const first = stats?.start ? Date.parse(`${stats.start}T00:00:00`) : Number.NaN
     const placed = withPhotos.map(entry => {
       const point = points.find(p => p.date && entry.date && p.date === entry.date)
         ?? points.find(p => p.label && entry.location && p.label === entry.location)
-      const at = entry.date ? Date.parse(`${entry.date}T00:00:00`) : NaN
+      const at = entry.date ? Date.parse(`${entry.date}T00:00:00`) : Number.NaN
       const dayNumber = Number.isFinite(at) && Number.isFinite(first)
         ? Math.floor((at - first) / 86_400_000) + 1
         : null
diff --git a/client/src/pages/login/worldDots.ts b/client/src/pages/login/worldDots.ts
index 4e542e7d7..1d9eaf844 100644
--- a/client/src/pages/login/worldDots.ts
+++ b/client/src/pages/login/worldDots.ts
@@ -16,7 +16,7 @@ export function worldDots(): { x: number; y: number }[] {
   const out: { x: number; y: number }[] = [];
   let cursor = 0;
   for (const part of PACKED.split('.')) {
-    cursor += parseInt(part, 36);
+    cursor += Number.parseInt(part, 36);
     out.push({ x: cursor % WORLD_GRID_W, y: Math.floor(cursor / WORLD_GRID_W) });
   }
   return out;
diff --git a/client/src/pages/tripPlanner/useTripPlanner.ts b/client/src/pages/tripPlanner/useTripPlanner.ts
index a3e37be74..d7ff6adc0 100644
--- a/client/src/pages/tripPlanner/useTripPlanner.ts
+++ b/client/src/pages/tripPlanner/useTripPlanner.ts
@@ -48,7 +48,7 @@ export function useTripPlanner() {
   // The route param is a string; convert once here so every downstream component
   // prop and store call gets a real number. An absent/invalid id becomes NaN,
   // which stays falsy in the `if (tripId)` guards below.
-  const tripId = id ? Number(id) : NaN
+  const tripId = id ? Number(id) : Number.NaN
   const navigate = useNavigate()
   const toast = useToast()
   const { t, language } = useTranslation()
diff --git a/client/src/store/slices/assignmentsSlice.ts b/client/src/store/slices/assignmentsSlice.ts
index cc551af51..8411a0724 100644
--- a/client/src/store/slices/assignmentsSlice.ts
+++ b/client/src/store/slices/assignmentsSlice.ts
@@ -18,7 +18,7 @@ export interface AssignmentsSlice {
 export const createAssignmentsSlice = (set: SetState, get: GetState): AssignmentsSlice => ({
   assignPlaceToDay: async (tripId, dayId, placeId, position) => {
     const state = get()
-    const place = state.places.find(p => p.id === parseInt(String(placeId)))
+    const place = state.places.find(p => p.id === Number.parseInt(String(placeId)))
     if (!place) return
 
     const tempId = Date.now() * -1
@@ -26,7 +26,7 @@ export const createAssignmentsSlice = (set: SetState, get: GetState): Assignment
     const insertIdx = position != null ? position : current.length
     const tempAssignment: Assignment = {
       id: tempId,
-      day_id: parseInt(String(dayId)),
+      day_id: Number.parseInt(String(dayId)),
       place_id: place.id,
       order_index: insertIdx,
       notes: null,
@@ -141,7 +141,7 @@ export const createAssignmentsSlice = (set: SetState, get: GetState): Assignment
     const insertAt = toOrderIndex !== null ? toOrderIndex : toItems.length
 
     const newToItems = [...toItems]
-    newToItems.splice(insertAt, 0, { ...assignment, day_id: parseInt(String(toDayId)) })
+    newToItems.splice(insertAt, 0, { ...assignment, day_id: Number.parseInt(String(toDayId)) })
     newToItems.forEach((a, i) => { a.order_index = i })
 
     set(s => ({
diff --git a/client/src/store/slices/dayNotesSlice.ts b/client/src/store/slices/dayNotesSlice.ts
index 7d795acc3..1d0eddb40 100644
--- a/client/src/store/slices/dayNotesSlice.ts
+++ b/client/src/store/slices/dayNotesSlice.ts
@@ -21,7 +21,7 @@ export const createDayNotesSlice = (set: SetState, get: GetState): DayNotesSlice
     try {
       await daysApi.update(tripId, dayId, { notes })
       set(state => ({
-        days: state.days.map(d => d.id === parseInt(String(dayId)) ? { ...d, notes } : d)
+        days: state.days.map(d => d.id === Number.parseInt(String(dayId)) ? { ...d, notes } : d)
       }))
     } catch (err: unknown) {
       throw new Error(getApiErrorMessage(err, 'Error updating notes'))
@@ -32,7 +32,7 @@ export const createDayNotesSlice = (set: SetState, get: GetState): DayNotesSlice
     try {
       await daysApi.update(tripId, dayId, { title })
       set(state => ({
-        days: state.days.map(d => d.id === parseInt(String(dayId)) ? { ...d, title } : d)
+        days: state.days.map(d => d.id === Number.parseInt(String(dayId)) ? { ...d, title } : d)
       }))
     } catch (err: unknown) {
       throw new Error(getApiErrorMessage(err, 'Error updating day name'))
diff --git a/client/src/sync/mutationQueue.ts b/client/src/sync/mutationQueue.ts
index 1c21ab487..0eff392d1 100644
--- a/client/src/sync/mutationQueue.ts
+++ b/client/src/sync/mutationQueue.ts
@@ -10,6 +10,7 @@ import { apiClient } from '../api/client'
 import { isAuthed } from './authGate'
 import { isEffectivelyOffline } from './networkMode'
 import { getOfflinePrefs } from './offlinePrefs'
+import { randomId } from '../utils/randomId'
 import type { QueuedMutation } from '../db/offlineDb'
 import type { Table } from 'dexie'
 
@@ -26,16 +27,15 @@ function getTable(resource: string): Table | undefined {
   return map[resource]
 }
 
-/** Generate a v4-style UUID using the platform crypto API. */
+/**
+ * Generate a v4-style UUID using the platform crypto API.
+ *
+ * The implementation moved to utils/randomId so the axios interceptor, which
+ * mints the same header for online writes, cannot drift away from it — this
+ * value becomes the X-Idempotency-Key and a duplicate silently drops a write.
+ */
 export function generateUUID(): string {
-  if (typeof crypto !== 'undefined' && crypto.randomUUID) {
-    return crypto.randomUUID()
-  }
-  // Fallback for environments without crypto.randomUUID (e.g. old Node)
-  return 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'.replace(/[xy]/g, (c) => {
-    const r = (Math.random() * 16) | 0
-    return (c === 'x' ? r : (r & 0x3) | 0x8).toString(16)
-  })
+  return randomId()
 }
 
 let _flushing = false
diff --git a/client/src/theme/applyAppearance.ts b/client/src/theme/applyAppearance.ts
index f5c583c22..b7a718394 100644
--- a/client/src/theme/applyAppearance.ts
+++ b/client/src/theme/applyAppearance.ts
@@ -59,9 +59,9 @@ function accentTextFor(hex: string): string {
   const c = hex.replace('#', '')
   const full = c.length === 3 ? c.split('').map((x) => x + x).join('') : c
   const toLin = (v: number) => (v <= 0.03928 ? v / 12.92 : Math.pow((v + 0.055) / 1.055, 2.4))
-  const r = toLin(parseInt(full.slice(0, 2), 16) / 255)
-  const g = toLin(parseInt(full.slice(2, 4), 16) / 255)
-  const b = toLin(parseInt(full.slice(4, 6), 16) / 255)
+  const r = toLin(Number.parseInt(full.slice(0, 2), 16) / 255)
+  const g = toLin(Number.parseInt(full.slice(2, 4), 16) / 255)
+  const b = toLin(Number.parseInt(full.slice(4, 6), 16) / 255)
   const luminance = 0.2126 * r + 0.7152 * g + 0.0722 * b
   return luminance > 0.45 ? '#111827' : '#ffffff'
 }
diff --git a/client/src/utils/formatters.ts b/client/src/utils/formatters.ts
index 75c51f1f2..feb045396 100644
--- a/client/src/utils/formatters.ts
+++ b/client/src/utils/formatters.ts
@@ -163,8 +163,8 @@ export function formatDate(dateStr: string | null | undefined, locale: string, t
 export function parseMeridiemTime(value: string | null | undefined): string | null {
   const match = (value || '').trim().match(/^(\d{1,2}):?(\d{2})?\s*(am|pm)$/i)
   if (!match) return null
-  let h = parseInt(match[1])
-  const m = match[2] ? parseInt(match[2]) : 0
+  let h = Number.parseInt(match[1])
+  const m = match[2] ? Number.parseInt(match[2]) : 0
   const isPm = match[3].toLowerCase() === 'pm'
   if (h === 12) h = isPm ? 12 : 0
   else if (isPm) h += 12
@@ -300,7 +300,7 @@ export function dayTotalCost(
 ): string | null {
   const da = assignments[String(dayId)] || []
   const entries = da.map(a => ({
-    amount: parseFloat(String(a.place?.price ?? '')) || 0,
+    amount: Number.parseFloat(String(a.place?.price ?? '')) || 0,
     currency: a.place?.currency || tripCurrency,
   }))
   return formatMoneySum(entries, base, locale, rates, { decimals: 0 })
diff --git a/client/src/utils/randomId.ts b/client/src/utils/randomId.ts
new file mode 100644
index 000000000..f9ae2ea1c
--- /dev/null
+++ b/client/src/utils/randomId.ts
@@ -0,0 +1,39 @@
+/**
+ * The one place idempotency keys are minted.
+ *
+ * Both producers — the offline queue's mutation id and the axios interceptor's
+ * per-request key — end up in the same `X-Idempotency-Key` header, which the
+ * server caches on (key, user_id, method, path). Two writes that share a key
+ * therefore collapse into one: the second gets the first one's cached response
+ * instead of being applied, and the user loses an edit with no error anywhere.
+ *
+ * `crypto.randomUUID` needs a secure context, and TREK's own quickstart is plain
+ * http://localhost:3000 with LAN installs on http://192.168.x.x — so on the
+ * deployments the README documents, randomUUID is undefined and the fallback is
+ * what actually runs. It has to be a real one. `getRandomValues` has no
+ * secure-context requirement and covers that gap; the Math.random rung below it
+ * exists only for a runtime with no Web Crypto at all.
+ *
+ * Lives in its own module rather than next to either caller because
+ * sync/mutationQueue imports api/client, so the dependency can only go one way.
+ */
+export function randomId(): string {
+  const c = globalThis.crypto
+  if (c && typeof c.randomUUID === 'function') return c.randomUUID()
+
+  if (c && typeof c.getRandomValues === 'function') {
+    const bytes = new Uint8Array(16)
+    c.getRandomValues(bytes)
+    // RFC 4122 version + variant bits, so the value still reads as a v4 UUID.
+    bytes[6] = (bytes[6] & 0x0f) | 0x40
+    bytes[8] = (bytes[8] & 0x3f) | 0x80
+    const hex = Array.from(bytes, b => b.toString(16).padStart(2, '0')).join('')
+    return `${hex.slice(0, 8)}-${hex.slice(8, 12)}-${hex.slice(12, 16)}-${hex.slice(16, 20)}-${hex.slice(20)}`
+  }
+
+  // Padded on purpose: `Math.random().toString(36).slice(2)` is not
+  // length-stable — 0.5 yields a single character and 0 yields the empty
+  // string, which the server reads as "no key" and skips deduplication for.
+  const rand = () => Math.random().toString(36).slice(2).padStart(10, '0').slice(0, 10)
+  return `${Date.now().toString(36)}-${rand()}-${rand()}`
+}
diff --git a/client/src/vacay/yearWindow.ts b/client/src/vacay/yearWindow.ts
index e83a00319..5d4bf770a 100644
--- a/client/src/vacay/yearWindow.ts
+++ b/client/src/vacay/yearWindow.ts
@@ -38,8 +38,8 @@ function startMonthDay(s: VacayYearSettings): { month: number; day: number } {
   if (s.year_type === 'anniversary') {
     if (!s.hire_date) return { month: 1, day: 1 }
     const parts = s.hire_date.split('-')
-    month = parseInt(parts[1], 10) || 1
-    day = parseInt(parts[2], 10) || 1
+    month = Number.parseInt(parts[1], 10) || 1
+    day = Number.parseInt(parts[2], 10) || 1
   }
   month = Math.min(12, Math.max(1, month))
   return { month, day: Math.min(day, daysAlwaysInMonth(month)) }
diff --git a/client/tests/unit/remoteEventHandler/budget.test.ts b/client/tests/unit/remoteEventHandler/budget.test.ts
index d1aa1ebbf..c6a2b965a 100644
--- a/client/tests/unit/remoteEventHandler/budget.test.ts
+++ b/client/tests/unit/remoteEventHandler/budget.test.ts
@@ -80,12 +80,15 @@ describe('remoteEventHandler > budget', () => {
       type: 'budget:member-paid-updated',
       itemId: 1,
       userId: 5,
-      paid: true,
+      // 1, not true: both emitters send `paid: body.paid ? 1 : 0`, and the handler
+      // stores the value verbatim. Asserting on `true` tested a payload the server
+      // never sends — the seeded value on the line below is a number for the same reason.
+      paid: 1,
     });
     const { budgetItems } = useTripStore.getState();
     const item = budgetItems.find(i => i.id === 1);
     const m = item?.members?.find(m => m.user_id === 5);
-    expect(m?.paid).toBe(true);
+    expect(m?.paid).toBe(1);
     // Other item members unchanged (member2 keeps its seeded paid value)
     const item2 = budgetItems.find(i => i.id === 2);
     expect(item2?.members?.[0].paid).toBe(1);
diff --git a/plugin-sdk/src/egress-policy.ts b/plugin-sdk/src/egress-policy.ts
index 45b3a3007..3ba721c41 100644
--- a/plugin-sdk/src/egress-policy.ts
+++ b/plugin-sdk/src/egress-policy.ts
@@ -106,7 +106,7 @@ function expandV6(ip: string): number[] | null {
   const groups =
     halves.length === 2 ? [...head, ...Array(8 - head.length - tail.length).fill('0'), ...tail] : head;
   if (groups.length !== 8) return null;
-  const nums = groups.map((x) => (x === '' ? NaN : parseInt(x, 16)));
+  const nums = groups.map((x) => (x === '' ? Number.NaN : Number.parseInt(x, 16)));
   return nums.some((n) => !Number.isInteger(n) || n < 0 || n > 0xffff) ? null : nums;
 }
 
diff --git a/server/src/app-config/derive.ts b/server/src/app-config/derive.ts
index 0d02eea01..a4b3d95d8 100644
--- a/server/src/app-config/derive.ts
+++ b/server/src/app-config/derive.ts
@@ -233,6 +233,12 @@ export function deriveIntegrations(raw: RawEnv) {
     overpassUrl: raw.OVERPASS_URL,
     overpassTimeoutMs: positiveNumberOr(raw.OVERPASS_TIMEOUT_MS, 12000),
     kitineraryExtractorPath: raw.KITINERARY_EXTRACTOR_PATH,
+    // Windows spells it Path; every other platform PATH. Split here so callers
+    // get a list and never re-implement the delimiter.
+    searchPath: (raw.PATH || raw.Path || '')
+      .split(process.platform === 'win32' ? ';' : ':')
+      .map(p => p.trim())
+      .filter(Boolean),
   };
 }
 
diff --git a/server/src/app-config/env.schema.ts b/server/src/app-config/env.schema.ts
index d2669bc41..4bf41ac3d 100644
--- a/server/src/app-config/env.schema.ts
+++ b/server/src/app-config/env.schema.ts
@@ -113,6 +113,12 @@ export const envSchema = z.object({
   OVERPASS_URL: anyString,
   OVERPASS_TIMEOUT_MS: positiveNumber,
   KITINERARY_EXTRACTOR_PATH: anyString,
+  // The OS search path. Not configuration anybody sets for TREK — it is here so
+  // the kitinerary probe can resolve its binary to an absolute path itself
+  // instead of handing an unqualified name to exec, which would re-resolve
+  // through whatever PATH held at that moment.
+  PATH: anyString,
+  Path: anyString,
 
   // Data / paths
   TREK_DB_FILE: anyString,
diff --git a/server/src/app-config/parsers.ts b/server/src/app-config/parsers.ts
index 2d75e4db3..ebaca568a 100644
--- a/server/src/app-config/parsers.ts
+++ b/server/src/app-config/parsers.ts
@@ -90,7 +90,7 @@ const DURATION_UNITS_MS: Record<string, number> = {
 export function parseDurationMs(value: string): number | null {
   const m = /^(\d+(?:\.\d+)?)\s*(ms|s|m|h|d|w|y)?$/i.exec(value.trim());
   if (!m) return null;
-  const n = parseFloat(m[1]);
+  const n = Number.parseFloat(m[1]);
   if (!Number.isFinite(n) || n <= 0) return null;
   return n * DURATION_UNITS_MS[(m[2] || 'ms').toLowerCase()];
 }
diff --git a/server/src/nest/admin/admin.helpers.ts b/server/src/nest/admin/admin.helpers.ts
index 2c984c210..9e9ede0e2 100644
--- a/server/src/nest/admin/admin.helpers.ts
+++ b/server/src/nest/admin/admin.helpers.ts
@@ -27,7 +27,7 @@ export function compareVersions(a: string, b: string): number {
   const parse = (v: string) => {
     const [base, pre] = v.split('-pre.');
     const parts = base.split('.').map(Number);
-    const n = pre !== undefined ? parseInt(pre, 10) : null;
+    const n = pre !== undefined ? Number.parseInt(pre, 10) : null;
     const preN = n !== null && Number.isFinite(n) ? n : null;
     return { parts, preN };
   };
diff --git a/server/src/nest/admin/admin.service.ts b/server/src/nest/admin/admin.service.ts
index 9cb35f9ab..5a50ab991 100644
--- a/server/src/nest/admin/admin.service.ts
+++ b/server/src/nest/admin/admin.service.ts
@@ -249,7 +249,7 @@ export class AdminService {
   }
 
   deleteUser(id: string, currentUserId: number) {
-    if (parseInt(id) === currentUserId) {
+    if (Number.parseInt(id) === currentUserId) {
       return { error: 'Cannot delete own account', status: 400 };
     }
 
@@ -328,8 +328,8 @@ export class AdminService {
   // ── Audit Log ──────────────────────────────────────────────────────────────
 
   getAuditLog(query: { limit?: string; offset?: string }) {
-    const limitRaw = parseInt(String(query.limit || '100'), 10);
-    const offsetRaw = parseInt(String(query.offset || '0'), 10);
+    const limitRaw = Number.parseInt(String(query.limit || '100'), 10);
+    const offsetRaw = Number.parseInt(String(query.offset || '0'), 10);
     const limit = Math.min(Math.max(Number.isFinite(limitRaw) ? limitRaw : 100, 1), 500);
     const offset = Math.max(Number.isFinite(offsetRaw) ? offsetRaw : 0, 0);
 
diff --git a/server/src/nest/atlas/atlas.service.ts b/server/src/nest/atlas/atlas.service.ts
index b966b9a0d..6d5d567d7 100644
--- a/server/src/nest/atlas/atlas.service.ts
+++ b/server/src/nest/atlas/atlas.service.ts
@@ -429,7 +429,7 @@ export class AtlasService {
       nextTrip.daysUntil = Math.max(0, diff);
     }
 
-    const tripYears = new Set(trips.filter((t) => t.start_date).map((t) => parseInt(t.start_date!.split('-')[0])));
+    const tripYears = new Set(trips.filter((t) => t.start_date).map((t) => Number.parseInt(t.start_date!.split('-')[0])));
     let streak = 0;
     const currentYear = new Date().getFullYear();
     for (let y = currentYear; y >= 2000; y--) {
diff --git a/server/src/nest/auth/registration-invites.service.ts b/server/src/nest/auth/registration-invites.service.ts
index a3426c17a..581592600 100644
--- a/server/src/nest/auth/registration-invites.service.ts
+++ b/server/src/nest/auth/registration-invites.service.ts
@@ -40,18 +40,18 @@ export class RegistrationInvitesService {
     createdBy: number,
     data: { max_uses?: string | number; expires_in_days?: string | number; trip_id?: string | number | null },
   ) {
-    const rawUses = parseInt(String(data.max_uses));
+    const rawUses = Number.parseInt(String(data.max_uses));
     const uses = rawUses === 0 ? 0 : Math.min(Math.max(rawUses || 1, 1), 5);
     const token = crypto.randomBytes(16).toString('hex');
     const expiresAt = data.expires_in_days
-      ? new Date(Date.now() + parseInt(String(data.expires_in_days)) * 86400000).toISOString()
+      ? new Date(Date.now() + Number.parseInt(String(data.expires_in_days)) * 86400000).toISOString()
       : null;
 
     // Optional trip binding: only persist a trip that actually exists, so a stale
     // or forged id can never bind (and never auto-adds anyone on registration).
     let tripId: number | null = null;
     if (data.trip_id != null && String(data.trip_id).trim() !== '') {
-      const parsed = parseInt(String(data.trip_id));
+      const parsed = Number.parseInt(String(data.trip_id));
       if (!Number.isInteger(parsed) || !this.db.get('SELECT id FROM trips WHERE id = ?', parsed)) {
         // Used to bind null silently, handing back a plain registration invite
         // the admin never asked for.
diff --git a/server/src/nest/backup/backup.impl.ts b/server/src/nest/backup/backup.impl.ts
index 16e91804f..518ada24b 100644
--- a/server/src/nest/backup/backup.impl.ts
+++ b/server/src/nest/backup/backup.impl.ts
@@ -47,7 +47,7 @@ export function formatSize(bytes: number): string {
 export function parseIntField(raw: unknown, fallback: number): number {
   if (typeof raw === 'number' && Number.isFinite(raw)) return Math.floor(raw);
   if (typeof raw === 'string' && raw.trim() !== '') {
-    const n = parseInt(raw, 10);
+    const n = Number.parseInt(raw, 10);
     if (Number.isFinite(n)) return n;
   }
   return fallback;
diff --git a/server/src/nest/booking-import/booking-import.service.ts b/server/src/nest/booking-import/booking-import.service.ts
index 0643e2184..1f042dc02 100644
--- a/server/src/nest/booking-import/booking-import.service.ts
+++ b/server/src/nest/booking-import/booking-import.service.ts
@@ -315,7 +315,7 @@ export class BookingImportService {
             reservationData.metadata && typeof reservationData.metadata === 'object'
               ? (reservationData.metadata as Record<string, unknown>)
               : null;
-          const price = meta && meta.price != null ? Number(meta.price) : NaN;
+          const price = meta && meta.price != null ? Number(meta.price) : Number.NaN;
           if (Number.isFinite(price) && price > 0) {
             try {
               const budgetData = {
diff --git a/server/src/nest/booking-import/kitinerary-extractor.service.ts b/server/src/nest/booking-import/kitinerary-extractor.service.ts
index 9fc6999eb..a9bbee3d9 100644
--- a/server/src/nest/booking-import/kitinerary-extractor.service.ts
+++ b/server/src/nest/booking-import/kitinerary-extractor.service.ts
@@ -5,11 +5,14 @@ import { tmpdir } from 'node:os';
 import { join, extname } from 'node:path';
 import { randomUUID } from 'node:crypto';
 import { readEnv } from '../../app-config';
-import { execSync } from 'node:child_process';
+import { execFileSync } from 'node:child_process';
 import { promisify } from 'node:util';
 import type { KiReservation } from './kitinerary.types';
 
 const execFileAsync = promisify(execFile);
+
+/** Also the leaf name looked for on each PATH entry. */
+const BINARY_NAME = 'kitinerary-extractor';
 const TIMEOUT_MS = 30_000;
 const MAX_BUFFER = 5 * 1024 * 1024;
 
@@ -89,16 +92,26 @@ export class KitineraryExtractorService implements OnModuleInit {
     // Debian/Ubuntu: /usr/lib/<triplet>/libexec/kf6/kitinerary-extractor
     try {
       for (const dir of readdirSync('/usr/lib')) {
-        const candidate = join('/usr/lib', dir, 'libexec', 'kf6', 'kitinerary-extractor');
+        const candidate = join('/usr/lib', dir, 'libexec', 'kf6', BINARY_NAME);
         if (existsSync(candidate)) return candidate;
       }
     } catch { /* not a Debian system */ }
 
-    // Fallback: binary in PATH
-    try {
-      execSync('kitinerary-extractor --version', { stdio: 'pipe', timeout: 3000 });
-      return 'kitinerary-extractor';
-    } catch { /* not in PATH */ }
+    // Fallback: binary on the search path — resolved to an absolute path here,
+    // not left as a bare name. Storing 'kitinerary-extractor' meant every later
+    // extraction re-resolved it through whatever PATH held at that moment, so on
+    // a bare-metal install (the official image sets KITINERARY_EXTRACTOR_PATH, so
+    // this branch is dead there) anyone who could write to a PATH directory could
+    // have their binary run as the TREK user. Probing the concrete file with
+    // execFileSync also drops the /bin/sh hop the old execSync string needed.
+    for (const dir of readEnv().integrations.searchPath) {
+      const candidate = join(dir, BINARY_NAME);
+      if (!existsSync(candidate)) continue;
+      try {
+        execFileSync(candidate, ['--version'], { stdio: 'pipe', timeout: 3000 });
+        return candidate;
+      } catch { /* present but not runnable — keep looking */ }
+    }
 
     return null;
   }
diff --git a/server/src/nest/integrations/airtrail-import.service.ts b/server/src/nest/integrations/airtrail-import.service.ts
index 280f86b0d..1265e9788 100644
--- a/server/src/nest/integrations/airtrail-import.service.ts
+++ b/server/src/nest/integrations/airtrail-import.service.ts
@@ -62,7 +62,7 @@ function flightSignature(flight: AirtrailFlightRaw): string | null {
 function orderConnectionChain(group: AirtrailFlightRaw[]): AirtrailFlightRaw[] | null {
   if (group.length < 2) return null;
   const norm = group.map(raw => ({ raw, n: normalizeFlight(raw) }));
-  const depMs = (n: (typeof norm)[number]['n']): number => (n.departure ? Date.parse(n.departure) : NaN);
+  const depMs = (n: (typeof norm)[number]['n']): number => (n.departure ? Date.parse(n.departure) : Number.NaN);
   if (norm.some(x => Number.isNaN(depMs(x.n)))) return null;
   norm.sort((a, b) => depMs(a.n) - depMs(b.n));
   const origin = norm[0].n.fromCode;
@@ -71,7 +71,7 @@ function orderConnectionChain(group: AirtrailFlightRaw[]): AirtrailFlightRaw[] |
     const next = norm[i].n;
     if (!prev.toCode || !next.fromCode || prev.toCode.toUpperCase() !== next.fromCode.toUpperCase()) return null;
     if (origin && next.toCode && next.toCode.toUpperCase() === origin.toUpperCase()) return null;
-    const arrMs = prev.arrival ? Date.parse(prev.arrival) : NaN;
+    const arrMs = prev.arrival ? Date.parse(prev.arrival) : Number.NaN;
     if (Number.isNaN(arrMs)) return null;
     const gap = depMs(next) - arrMs;
     if (gap < 0 || gap > 24 * 3600 * 1000) return null;
diff --git a/server/src/nest/integrations/airtrail-sync.job.ts b/server/src/nest/integrations/airtrail-sync.job.ts
index 821783d7f..5e76527b7 100644
--- a/server/src/nest/integrations/airtrail-sync.job.ts
+++ b/server/src/nest/integrations/airtrail-sync.job.ts
@@ -22,7 +22,7 @@ export class AirtrailSyncJob implements OnApplicationBootstrap {
   onApplicationBootstrap(): void {
     if (!this.registrar.isEnabled()) return;
     const value = this.db.get<{ value: string }>('SELECT value FROM app_settings WHERE key = ?', 'airtrail_poll_interval_minutes')?.value;
-    const raw = parseInt(value || '5', 10);
+    const raw = Number.parseInt(value || '5', 10);
     const minutes = Number.isFinite(raw) && raw >= 1 && raw <= 59 ? raw : 5;
     logInfo(`AirTrail sync: scheduled every ${minutes}m`);
     this.registrar.register('airtrail-sync', `*/${minutes} * * * *`, () => this.tick());
diff --git a/server/src/nest/llm-parse/text-extract.ts b/server/src/nest/llm-parse/text-extract.ts
index c032372dd..397ad94e1 100644
--- a/server/src/nest/llm-parse/text-extract.ts
+++ b/server/src/nest/llm-parse/text-extract.ts
@@ -77,7 +77,7 @@ function decodeEntities(s: string): string {
   return s.replace(/&(#\d{1,7}|#[xX][0-9a-fA-F]{1,6}|[A-Za-z][A-Za-z0-9]{1,30});/g, (whole, ref: string) => {
     if (ref[0] === '#') {
       const hex = ref[1] === 'x' || ref[1] === 'X';
-      return entityCodePoint(parseInt(hex ? ref.slice(2) : ref.slice(1), hex ? 16 : 10)) ?? whole;
+      return entityCodePoint(Number.parseInt(hex ? ref.slice(2) : ref.slice(1), hex ? 16 : 10)) ?? whole;
     }
     // Case matters (&Uuml; vs &uuml;); only fall back to lower case for names
     // that are shouted in old templates.
diff --git a/server/src/nest/maps/maps.controller.ts b/server/src/nest/maps/maps.controller.ts
index 07b75d872..644889fb0 100644
--- a/server/src/nest/maps/maps.controller.ts
+++ b/server/src/nest/maps/maps.controller.ts
@@ -163,7 +163,7 @@ export class MapsController {
     // empty result, not a missing resource, and one 404 per photo-less place gets
     // the user's IP banned by any 404-rate IPS in front of TREK (#1727).
     try {
-      return await this.maps.photo(user.id, placeId, parseFloat(lat as string), parseFloat(lng as string), name);
+      return await this.maps.photo(user.id, placeId, Number.parseFloat(lat as string), Number.parseFloat(lng as string), name);
     } catch (err: unknown) {
       const status = (err as { status?: number }).status || 500;
       if (status >= 500) console.error('Place photo error:', err);
diff --git a/server/src/nest/maps/maps.helpers.ts b/server/src/nest/maps/maps.helpers.ts
index dffbf5427..072579bbb 100644
--- a/server/src/nest/maps/maps.helpers.ts
+++ b/server/src/nest/maps/maps.helpers.ts
@@ -328,10 +328,10 @@ function osmPeriods(dayIdx: number, timePart: string): OpeningPeriod[] {
   const day = (dayIdx + 1) % 7;
   const periods: OpeningPeriod[] = [];
   for (const match of timePart.matchAll(OSM_TIME_RANGE)) {
-    const openHour = parseInt(match[1], 10);
-    const openMinute = parseInt(match[2], 10);
-    let closeHour = parseInt(match[3], 10);
-    const closeMinute = parseInt(match[4], 10);
+    const openHour = Number.parseInt(match[1], 10);
+    const openMinute = Number.parseInt(match[2], 10);
+    let closeHour = Number.parseInt(match[3], 10);
+    const closeMinute = Number.parseInt(match[4], 10);
     if (openHour > 23 || openMinute > 59 || closeHour > 24 || closeMinute > 59) continue;
     // OSM writes the end of a day as 24:00, a clock reading Google's numbering has no
     // hour 24 — that is midnight of the following day, same as any range that wraps.
@@ -421,8 +421,8 @@ export function parseOpeningHours(ohString: string): {
     if (timeRanges.length > 0) {
       const nowMins = now.getHours() * 60 + now.getMinutes();
       openNow = timeRanges.some((m) => {
-        const start = parseInt(m[1]) * 60 + parseInt(m[2]);
-        const end = parseInt(m[3]) * 60 + parseInt(m[4]);
+        const start = Number.parseInt(m[1]) * 60 + Number.parseInt(m[2]);
+        const end = Number.parseInt(m[3]) * 60 + Number.parseInt(m[4]);
         return end > start ? nowMins >= start && nowMins < end : nowMins >= start || nowMins < end;
       });
     }
diff --git a/server/src/nest/maps/maps.service.ts b/server/src/nest/maps/maps.service.ts
index f8447f5b0..bbd3f3c19 100644
--- a/server/src/nest/maps/maps.service.ts
+++ b/server/src/nest/maps/maps.service.ts
@@ -639,8 +639,8 @@ export class MapsService {
     return data.map((item) => {
       // Number.isFinite, not `|| null`: a place on the equator or prime
       // meridian has a legitimate 0 coordinate.
-      const lat = parseFloat(item.lat);
-      const lng = parseFloat(item.lon);
+      const lat = Number.parseFloat(item.lat);
+      const lng = Number.parseFloat(item.lon);
       return {
         google_place_id: null,
         google_ftid: null,
@@ -714,8 +714,8 @@ export class MapsService {
       const best = data
         .map((item) => ({
           item,
-          lat: parseFloat(item.lat),
-          lng: parseFloat(item.lon),
+          lat: Number.parseFloat(item.lat),
+          lng: Number.parseFloat(item.lon),
         }))
         .filter(({ item, lat: hitLat, lng: hitLng }) => {
           if (!Number.isFinite(hitLat) || !Number.isFinite(hitLng)) return false;
@@ -773,8 +773,8 @@ export class MapsService {
       const data = (await res.json()) as NominatimResult[];
       const item = data[0];
       if (!item) return null;
-      const lat = parseFloat(item.lat);
-      const lng = parseFloat(item.lon);
+      const lat = Number.parseFloat(item.lat);
+      const lng = Number.parseFloat(item.lon);
       return {
         name: item.name || item.display_name?.split(',')[0] || '',
         address: item.display_name || '',
@@ -2023,11 +2023,11 @@ export class MapsService {
     // them several ways: /@lat,lng,zoom · !3dlat!4dlng (map data param) · ?q=/?ll=.
     const extractCoords = (s: string): { lat: number; lng: number } | null => {
       const at = s.match(/@(-?\d+\.\d+),(-?\d+\.\d+)/);
-      if (at) return { lat: parseFloat(at[1]), lng: parseFloat(at[2]) };
+      if (at) return { lat: Number.parseFloat(at[1]), lng: Number.parseFloat(at[2]) };
       const data = s.match(/!3d(-?\d+\.\d+)!4d(-?\d+\.\d+)/);
-      if (data) return { lat: parseFloat(data[1]), lng: parseFloat(data[2]) };
+      if (data) return { lat: Number.parseFloat(data[1]), lng: Number.parseFloat(data[2]) };
       const q = s.match(/[?&](?:q|ll)=(-?\d+\.\d+),(-?\d+\.\d+)/);
-      if (q) return { lat: parseFloat(q[1]), lng: parseFloat(q[2]) };
+      if (q) return { lat: Number.parseFloat(q[1]), lng: Number.parseFloat(q[2]) };
       return null;
     };
 
diff --git a/server/src/nest/notifications/mailer/mailer.service.ts b/server/src/nest/notifications/mailer/mailer.service.ts
index f15937cb2..79e9932f2 100644
--- a/server/src/nest/notifications/mailer/mailer.service.ts
+++ b/server/src/nest/notifications/mailer/mailer.service.ts
@@ -46,11 +46,11 @@ export class MailerService {
     if (!host || !port || !from) return null;
     return {
       host,
-      port: parseInt(port, 10),
+      port: Number.parseInt(port, 10),
       user: user || '',
       pass: pass || '',
       from,
-      secure: parseInt(port, 10) === 465,
+      secure: Number.parseInt(port, 10) === 465,
     };
   }
 
diff --git a/server/src/nest/notifications/notifications.controller.ts b/server/src/nest/notifications/notifications.controller.ts
index 5cdad0e55..f26c3b924 100644
--- a/server/src/nest/notifications/notifications.controller.ts
+++ b/server/src/nest/notifications/notifications.controller.ts
@@ -132,8 +132,8 @@ export class NotificationsController {
     @Query('unread_only') unreadOnly?: string,
   ) {
     return this.notifications.listInApp(user.id, {
-      limit: Math.min(parseInt(limit as string) || 20, 50),
-      offset: parseInt(offset as string) || 0,
+      limit: Math.min(Number.parseInt(limit as string) || 20, 50),
+      offset: Number.parseInt(offset as string) || 0,
       unreadOnly: unreadOnly === 'true',
     });
   }
@@ -197,7 +197,7 @@ export class NotificationsController {
 
   /** parseInt + the legacy "Invalid id" 400 guard, shared by the /:id handlers. */
   private parseId(idParam: string): number {
-    const id = parseInt(idParam);
+    const id = Number.parseInt(idParam);
     if (isNaN(id)) {
       throw new HttpException({ error: 'Invalid id' }, 400);
     }
diff --git a/server/src/nest/packing/packing.controller.ts b/server/src/nest/packing/packing.controller.ts
index f0f06287b..9e3d9bdd3 100644
--- a/server/src/nest/packing/packing.controller.ts
+++ b/server/src/nest/packing/packing.controller.ts
@@ -228,7 +228,7 @@ export class PackingController {
     @Headers('x-socket-id') socketId?: string,
   ) {
     // You can drop your own pledge; the owner can remove anyone's.
-    const target = parseInt(userId);
+    const target = Number.parseInt(userId);
     const item = this.packing.removeContributor(tripId, id, target);
     if (!item) {
       throw new HttpException({ error: 'Item not found' }, 404);
diff --git a/server/src/nest/packing/packing.service.ts b/server/src/nest/packing/packing.service.ts
index 01c169ccb..502d6bb7c 100644
--- a/server/src/nest/packing/packing.service.ts
+++ b/server/src/nest/packing/packing.service.ts
@@ -434,7 +434,7 @@ export class PackingService {
       for (const item of items) {
         if (!item.name?.trim()) continue;
         const checked = item.checked ? 1 : 0;
-        const weight = item.weight_grams ? parseInt(String(item.weight_grams)) || null : null;
+        const weight = item.weight_grams ? Number.parseInt(String(item.weight_grams)) || null : null;
 
         // Resolve bag by name if provided
         let bagId = null;
diff --git a/server/src/nest/places/gpx-export.helpers.ts b/server/src/nest/places/gpx-export.helpers.ts
index 41b878876..46c3dffc6 100644
Binary files a/server/src/nest/places/gpx-export.helpers.ts and b/server/src/nest/places/gpx-export.helpers.ts differ
diff --git a/server/src/nest/places/kml-import.helpers.ts b/server/src/nest/places/kml-import.helpers.ts
index 599cffff1..4f0373bd9 100644
--- a/server/src/nest/places/kml-import.helpers.ts
+++ b/server/src/nest/places/kml-import.helpers.ts
@@ -109,7 +109,7 @@ export function parseKmlLineStringCoordinates(value: unknown): Array<{ lat: numb
       const parts = coord.split(',');
       const lng = Number.parseFloat(parts[0] ?? '');
       const lat = Number.parseFloat(parts[1] ?? '');
-      const eleRaw = parts[2] != null ? Number.parseFloat(parts[2]) : NaN;
+      const eleRaw = parts[2] != null ? Number.parseFloat(parts[2]) : Number.NaN;
       if (!Number.isFinite(lat) || !Number.isFinite(lng)) return null;
       return { lat, lng, ele: Number.isFinite(eleRaw) ? eleRaw : null };
     })
diff --git a/server/src/nest/places/places.service.ts b/server/src/nest/places/places.service.ts
index abd50cd45..8fa1e82fd 100644
--- a/server/src/nest/places/places.service.ts
+++ b/server/src/nest/places/places.service.ts
@@ -623,7 +623,7 @@ export class PlacesService {
     if (!gpx) return null;
 
     const str = (v: unknown) => (v != null ? String(v).trim() : null);
-    const num = (v: unknown) => { const n = parseFloat(String(v)); return isNaN(n) ? null : n; };
+    const num = (v: unknown) => { const n = Number.parseFloat(String(v)); return isNaN(n) ? null : n; };
 
     // Routes and tracks rarely carry their own <name>. Without one they all fall back to the
     // same generic label, so name-based dedup drops every import after the first. Derive a
diff --git a/server/src/nest/plugins/install/safe-extract.ts b/server/src/nest/plugins/install/safe-extract.ts
index dac256435..93dae2b68 100644
--- a/server/src/nest/plugins/install/safe-extract.ts
+++ b/server/src/nest/plugins/install/safe-extract.ts
@@ -82,7 +82,7 @@ function readTarGz(buf: Buffer, lim: Required<ExtractLimits>): Member[] {
     let name = block.subarray(0, 100).toString('utf8').replace(/\0.*$/, '');
     const prefix = block.subarray(345, 500).toString('utf8').replace(/\0.*$/, '');
     if (prefix) name = `${prefix}/${name}`;
-    const size = parseInt(block.subarray(124, 136).toString('utf8').replace(/\0.*$/, '').trim() || '0', 8);
+    const size = Number.parseInt(block.subarray(124, 136).toString('utf8').replace(/\0.*$/, '').trim() || '0', 8);
     // A negative size walks the cursor backwards: `off += 512` and then
     // `off += Math.ceil(size / 512) * 512` cancel out at -512 and go negative
     // below it, so the same header is read forever while every pass appends a
diff --git a/server/src/nest/plugins/runtime/egress-policy.ts b/server/src/nest/plugins/runtime/egress-policy.ts
index 36663f8a5..f9cc3ac14 100644
--- a/server/src/nest/plugins/runtime/egress-policy.ts
+++ b/server/src/nest/plugins/runtime/egress-policy.ts
@@ -84,7 +84,7 @@ function expandV6(ip: string): number[] | null {
   const groups =
     halves.length === 2 ? [...head, ...Array(8 - head.length - tail.length).fill('0'), ...tail] : head;
   if (groups.length !== 8) return null;
-  const nums = groups.map((x) => (x === '' ? NaN : parseInt(x, 16)));
+  const nums = groups.map((x) => (x === '' ? Number.NaN : Number.parseInt(x, 16)));
   return nums.some((n) => !Number.isInteger(n) || n < 0 || n > 0xffff) ? null : nums;
 }
 
diff --git a/server/src/nest/trip-invite/trip-invite.controller.ts b/server/src/nest/trip-invite/trip-invite.controller.ts
index ee3269493..505ea5845 100644
--- a/server/src/nest/trip-invite/trip-invite.controller.ts
+++ b/server/src/nest/trip-invite/trip-invite.controller.ts
@@ -47,7 +47,7 @@ export class TripInviteLinkController {
   ) {
     this.requireManage(tripId, user);
     const days = body?.expires_in_days != null && String(body.expires_in_days).trim() !== ''
-      ? parseInt(String(body.expires_in_days))
+      ? Number.parseInt(String(body.expires_in_days))
       : null;
     const info = this.invites.createOrRotate(tripId, user.id, Number.isFinite(days as number) ? days : null);
     this.audit.writeAudit({ userId: user.id, action: 'trip.invite_link_create', resource: tripId, ip: getClientIp(req), details: { expires_in_days: days } });
diff --git a/server/src/nest/trip-members/trip-members.controller.ts b/server/src/nest/trip-members/trip-members.controller.ts
index eef37bf91..d2a758e1b 100644
--- a/server/src/nest/trip-members/trip-members.controller.ts
+++ b/server/src/nest/trip-members/trip-members.controller.ts
@@ -84,7 +84,7 @@ export class TripMembersController {
     if (!access) {
       throw new HttpException({ error: 'Trip not found' }, 404);
     }
-    const targetId = parseInt(userId);
+    const targetId = Number.parseInt(userId);
     if (targetId !== user.id && !this.roster.can('member_manage', user.role, access.user_id, user.id, access.user_id !== user.id)) {
       throw new HttpException({ error: 'No permission to remove members' }, 403);
     }
@@ -139,7 +139,7 @@ export class TripMembersController {
   @RequireTripOwner('Only the owner can manage guests', { param: 'id' })
   renameGuest(@CurrentUser() user: User, @Param('id') id: string, @Param('userId') userId: string, @Body() body: TripRenameGuestDto) {
     try {
-      if (!this.roster.renameGuest(id, parseInt(userId), body.name)) {
+      if (!this.roster.renameGuest(id, Number.parseInt(userId), body.name)) {
         throw new HttpException({ error: 'Guest not found' }, 404);
       }
       return { success: true };
@@ -154,7 +154,7 @@ export class TripMembersController {
   @UseGuards(TripOwnerGuard)
   @RequireTripOwner('Only the owner can manage guests', { param: 'id' })
   deleteGuest(@CurrentUser() user: User, @Param('id') id: string, @Param('userId') userId: string) {
-    if (!this.roster.deleteGuest(id, parseInt(userId))) {
+    if (!this.roster.deleteGuest(id, Number.parseInt(userId))) {
       throw new HttpException({ error: 'Guest not found' }, 404);
     }
     return { success: true };
diff --git a/server/src/nest/vacay/vacay.controller.ts b/server/src/nest/vacay/vacay.controller.ts
index 435152cd1..40325877b 100644
--- a/server/src/nest/vacay/vacay.controller.ts
+++ b/server/src/nest/vacay/vacay.controller.ts
@@ -83,7 +83,7 @@ export class VacayController {
     @Body() body: VacayUpdateHolidayCalendarDto,
     @Headers('x-socket-id') socketId?: string,
   ) {
-    const id = parseInt(idParam);
+    const id = Number.parseInt(idParam);
     const planId = this.vacay.getActivePlanId(user.id);
     const calendar = this.vacay.updateHolidayCalendar(id, planId, body, socketId);
     if (!calendar) {
@@ -94,7 +94,7 @@ export class VacayController {
 
   @Delete('plan/holiday-calendars/:id')
   deleteHolidayCalendar(@CurrentUser() user: User, @Param('id') idParam: string, @Headers('x-socket-id') socketId?: string) {
-    const id = parseInt(idParam);
+    const id = Number.parseInt(idParam);
     const planId = this.vacay.getActivePlanId(user.id);
     if (!this.vacay.deleteHolidayCalendar(id, planId, socketId)) {
       throw new HttpException({ error: 'Calendar not found' }, 404);
@@ -109,7 +109,7 @@ export class VacayController {
     @Headers('x-socket-id') socketId?: string,
   ) {
     const planId = this.vacay.getActivePlanId(user.id);
-    const userId = body.target_user_id ? parseInt(String(body.target_user_id)) : user.id;
+    const userId = body.target_user_id ? Number.parseInt(String(body.target_user_id)) : user.id;
     if (!this.vacay.getPlanUsers(planId).find((u) => u.id === userId)) {
       throw new HttpException({ error: 'User not in plan' }, 403);
     }
@@ -187,7 +187,7 @@ export class VacayController {
 
   @Delete('years/:year')
   deleteYear(@CurrentUser() user: User, @Param('year') yearParam: string, @Headers('x-socket-id') socketId?: string) {
-    const year = parseInt(yearParam);
+    const year = Number.parseInt(yearParam);
     const planId = this.vacay.getActivePlanId(user.id);
     return { years: this.vacay.deleteYear(planId, year, socketId) };
   }
@@ -222,8 +222,8 @@ export class VacayController {
   ) {
     const planId = this.vacay.getActivePlanId(user.id);
     let userId = user.id;
-    if (body.target_user_id && parseInt(String(body.target_user_id)) !== user.id) {
-      const tid = parseInt(String(body.target_user_id));
+    if (body.target_user_id && Number.parseInt(String(body.target_user_id)) !== user.id) {
+      const tid = Number.parseInt(String(body.target_user_id));
       if (!this.vacay.getPlanUsers(planId).find((u) => u.id === tid)) {
         throw new HttpException({ error: 'User not in plan' }, 403);
       }
@@ -249,7 +249,7 @@ export class VacayController {
 
   @Get('stats/:year')
   stats(@CurrentUser() user: User, @Param('year') yearParam: string) {
-    const year = parseInt(yearParam);
+    const year = Number.parseInt(yearParam);
     const planId = this.vacay.getActivePlanId(user.id);
     return { stats: this.vacay.getStats(planId, year) };
   }
@@ -261,9 +261,9 @@ export class VacayController {
     @Body() body: VacayUpdateStatsDto,
     @Headers('x-socket-id') socketId?: string,
   ) {
-    const year = parseInt(yearParam);
+    const year = Number.parseInt(yearParam);
     const planId = this.vacay.getActivePlanId(user.id);
-    const userId = body.target_user_id ? parseInt(String(body.target_user_id)) : user.id;
+    const userId = body.target_user_id ? Number.parseInt(String(body.target_user_id)) : user.id;
     if (!this.vacay.getPlanUsers(planId).find((u) => u.id === userId)) {
       throw new HttpException({ error: 'User not in plan' }, 403);
     }
@@ -286,7 +286,7 @@ export class VacayController {
     if (!body.user_id) {
       throw new HttpException({ error: 'user_id required' }, 400);
     }
-    const result = this.vacay.shareCalendar(user.id, user.email, parseInt(String(body.user_id)), socketId);
+    const result = this.vacay.shareCalendar(user.id, user.email, Number.parseInt(String(body.user_id)), socketId);
     if (result.error) {
       throw new HttpException({ error: result.error }, result.status!);
     }
@@ -310,7 +310,7 @@ export class VacayController {
     @Body() body: VacayShareUpdateDto,
     @Headers('x-socket-id') socketId?: string,
   ) {
-    if (!this.vacay.setShareHidden(parseInt(idParam), user.id, body.hidden, socketId)) {
+    if (!this.vacay.setShareHidden(Number.parseInt(idParam), user.id, body.hidden, socketId)) {
       throw new HttpException({ error: 'Share not found' }, 404);
     }
     return { success: true };
@@ -318,7 +318,7 @@ export class VacayController {
 
   @Delete('shares/:id')
   deleteShare(@CurrentUser() user: User, @Param('id') idParam: string, @Headers('x-socket-id') socketId?: string) {
-    if (!this.vacay.removeShare(parseInt(idParam), user.id, socketId)) {
+    if (!this.vacay.removeShare(Number.parseInt(idParam), user.id, socketId)) {
       throw new HttpException({ error: 'Share not found' }, 404);
     }
     return { success: true };
diff --git a/server/src/nest/vacay/vacay.service.ts b/server/src/nest/vacay/vacay.service.ts
index cff2de8d3..128015624 100644
--- a/server/src/nest/vacay/vacay.service.ts
+++ b/server/src/nest/vacay/vacay.service.ts
@@ -158,7 +158,7 @@ function normalizeYearType(value: unknown): 'calendar' | 'fiscal' | 'anniversary
  * ending on Jan 1 (the calendar default) stops inside the previous year.
  */
 function windowEndYear(end: string): number {
-  const y = parseInt(end.slice(0, 4), 10);
+  const y = Number.parseInt(end.slice(0, 4), 10);
   return end.endsWith('-01-01') ? y - 1 : y;
 }
 
@@ -255,8 +255,8 @@ export class VacayService {
     let day = s.year_start_day || 1;
     if (s.year_type === 'anniversary') {
       const parts = s.hire_date!.split('-');
-      month = parseInt(parts[1], 10) || 1;
-      day = parseInt(parts[2], 10) || 1;
+      month = Number.parseInt(parts[1], 10) || 1;
+      day = Number.parseInt(parts[2], 10) || 1;
     }
     month = Math.min(12, Math.max(1, month));
     // A Feb 29 hire date (or a stored Feb 30) would name a boundary that most years
@@ -272,7 +272,7 @@ export class VacayService {
    * plain calendar year, which is exactly what a 'calendar' user resolves to.
    */
   private viewerWindow(year: number | string, viewerId?: number): { start: string; end: string } {
-    const y = typeof year === 'number' ? year : parseInt(year, 10);
+    const y = typeof year === 'number' ? year : Number.parseInt(year, 10);
     // A non-numeric year matched nothing under the old date prefix; an empty range
     // matches nothing either, so a bad parameter still yields an empty result.
     if (!Number.isFinite(y)) return { start: '', end: '' };
@@ -316,8 +316,8 @@ export class VacayService {
     data: { year_type?: unknown; year_start_month?: unknown; year_start_day?: unknown; hire_date?: unknown },
   ): VacayUserSettings {
     const type = normalizeYearType(data.year_type);
-    const month = Math.min(12, Math.max(1, parseInt(String(data.year_start_month ?? 1), 10) || 1));
-    const day = Math.min(31, Math.max(1, parseInt(String(data.year_start_day ?? 1), 10) || 1));
+    const month = Math.min(12, Math.max(1, Number.parseInt(String(data.year_start_month ?? 1), 10) || 1));
+    const day = Math.min(31, Math.max(1, Number.parseInt(String(data.year_start_day ?? 1), 10) || 1));
     const hire = typeof data.hire_date === 'string' && /^\d{4}-\d{2}-\d{2}$/.test(data.hire_date) ? data.hire_date : null;
     this.db.run(`
     INSERT INTO vacay_user_settings (user_id, year_type, year_start_month, year_start_day, hire_date)
diff --git a/server/src/nest/weather/weather.impl.ts b/server/src/nest/weather/weather.impl.ts
index e9d4624f7..613c8bffc 100644
--- a/server/src/nest/weather/weather.impl.ts
+++ b/server/src/nest/weather/weather.impl.ts
@@ -49,7 +49,7 @@ async function fetchOpenMeteo(url: string): Promise<{ response: Response; data:
 function coord(value: string, max: number, label: string): number {
   // Number('') and Number('  ') are 0, which would silently geolocate the Gulf
   // of Guinea instead of failing, so an empty value is rejected outright.
-  const n = String(value ?? '').trim() === '' ? NaN : Number(value);
+  const n = String(value ?? '').trim() === '' ? Number.NaN : Number(value);
   if (!Number.isFinite(n) || Math.abs(n) > max) {
     throw new ApiError(400, `Invalid ${label}`);
   }
@@ -199,8 +199,8 @@ const TTL_CURRENT_MS  = 15 * 60 * 1000;      // 15 minutes
 const TTL_CLIMATE_MS  = 24 * 60 * 60 * 1000; // 24 hours
 
 export function cacheKey(lat: string, lng: string, date?: string): string {
-  const rlat = parseFloat(lat).toFixed(2);
-  const rlng = parseFloat(lng).toFixed(2);
+  const rlat = Number.parseFloat(lat).toFixed(2);
+  const rlng = Number.parseFloat(lng).toFixed(2);
   return `${rlat}_${rlng}_${date || 'current'}`;
 }
 
diff --git a/server/src/utils/ipv6.ts b/server/src/utils/ipv6.ts
index 142221661..97fd4bb72 100644
--- a/server/src/utils/ipv6.ts
+++ b/server/src/utils/ipv6.ts
@@ -27,7 +27,7 @@ export function expandIpv6(ip: string): number[] | null {
   const groups =
     halves.length === 2 ? [...head, ...Array(8 - head.length - tail.length).fill('0'), ...tail] : head;
   if (groups.length !== 8) return null;
-  const nums = groups.map((x) => (x === '' ? NaN : parseInt(x, 16)));
+  const nums = groups.map((x) => (x === '' ? Number.NaN : Number.parseInt(x, 16)));
   return nums.some((n) => !Number.isInteger(n) || n < 0 || n > 0xffff) ? null : nums;
 }
 
diff --git a/server/tests/unit/nest/admin.controller.test.ts b/server/tests/unit/nest/admin.controller.test.ts
index daffb4c35..b8f718221 100644
--- a/server/tests/unit/nest/admin.controller.test.ts
+++ b/server/tests/unit/nest/admin.controller.test.ts
@@ -153,12 +153,12 @@ describe('AdminController error envelope fallbacks', () => {
 });
 
 describe('AdminController read-only getters', () => {
-  it('return service values verbatim', () => {
+  it('return service values verbatim', async () => {
     expect(adminCtl(svc({ resetUserPasskeys: vi.fn().mockReturnValue({ email: 'a@b.c', deleted: 2 }) } as Partial<AdminService>)).resetUserPasskeys(user, '4', req)).toEqual({ success: true, deleted: 2 });
     expect(adminCtl(svc({ getStats: vi.fn().mockReturnValue({ users: 3 }) } as Partial<AdminService>)).stats()).toEqual({ users: 3 });
     expect(adminCtl(svc({ getPermissions: vi.fn().mockReturnValue({ a: 1 }) } as Partial<AdminService>)).permissions()).toEqual({ a: 1 });
     expect(adminCtl(svc({ getAuditLog: vi.fn().mockReturnValue({ entries: [] }) } as Partial<AdminService>)).auditLog({})).toEqual({ entries: [] });
-    expect(adminCtl(svc({ checkVersion: vi.fn().mockResolvedValue({ current: '1' }) } as Partial<AdminService>)).versionCheck()).resolves.toEqual({ current: '1' });
+    await expect(adminCtl(svc({ checkVersion: vi.fn().mockResolvedValue({ current: '1' }) } as Partial<AdminService>)).versionCheck()).resolves.toEqual({ current: '1' });
     expect(adminCtl(svc(), undefined, undefined, {}, { listInvites: vi.fn().mockReturnValue([{ id: 1 }]) }).listInvites()).toEqual({ invites: [{ id: 1 }] });
     expect(adminCtl(svc({ listAddons: vi.fn().mockReturnValue([{ id: 'mcp' }]) } as Partial<AdminService>)).listAddons()).toEqual({ addons: [{ id: 'mcp' }] });
     expect(adminCtl(svc(), undefined, undefined, { listAllMcpTokens: vi.fn().mockReturnValue([{ id: 1 }]) }).listMcpTokens()).toEqual({ tokens: [{ id: 1 }] });
diff --git a/server/tests/unit/nest/booking-import/kitinerary-extractor.service.test.ts b/server/tests/unit/nest/booking-import/kitinerary-extractor.service.test.ts
index 1ebf54290..cfd21e0ea 100644
--- a/server/tests/unit/nest/booking-import/kitinerary-extractor.service.test.ts
+++ b/server/tests/unit/nest/booking-import/kitinerary-extractor.service.test.ts
@@ -8,11 +8,11 @@ import { describe, it, expect, vi, beforeEach } from 'vitest';
  * at all, and every branch that resolves it is a filesystem lookup that behaves
  * differently on the three platforms TREK ships to.
  */
-const { existsSync, readdirSync, readEnv, execSync, execFile } = vi.hoisted(() => ({
+const { existsSync, readdirSync, readEnv, execFileSync, execFile } = vi.hoisted(() => ({
   existsSync: vi.fn(),
   readdirSync: vi.fn(),
   readEnv: vi.fn(),
-  execSync: vi.fn(),
+  execFileSync: vi.fn(),
   // A plain function, because the service promisifies it at module load.
   execFile: vi.fn(),
 }));
@@ -23,16 +23,23 @@ vi.mock('node:fs', () => ({
   writeFileSync: vi.fn(),
   unlinkSync: vi.fn(),
 }));
-// The last branch of the probe shells out. Unmocked, the suite spawns a real
-// process on every machine and comes back green-or-red depending on whether the
-// developer happens to have KItinerary installed.
-vi.mock('node:child_process', () => ({ execSync, execFile }));
+// The last branch of the probe runs the candidate to see whether it works.
+// Unmocked, the suite spawns a real process on every machine and comes back
+// green-or-red depending on whether the developer happens to have KItinerary
+// installed.
+vi.mock('node:child_process', () => ({ execFileSync, execFile }));
 vi.mock('../../../../src/app-config', () => ({ readEnv }));
 
+import { join } from 'node:path';
 import { KitineraryExtractorService } from '../../../../src/nest/booking-import/kitinerary-extractor.service';
 
-function boot(env: { kitineraryExtractorPath?: string } = {}) {
-  readEnv.mockReturnValue({ integrations: env });
+// The probe builds candidates with path.join, so the expectations have to as
+// well — on Windows the separator is a backslash and a hardcoded '/usr/...'
+// string would never match.
+const onPath = (dir: string) => join(dir, 'kitinerary-extractor');
+
+function boot(env: { kitineraryExtractorPath?: string; searchPath?: string[] } = {}) {
+  readEnv.mockReturnValue({ integrations: { searchPath: [], ...env } });
   const svc = new KitineraryExtractorService();
   svc.onModuleInit();
   return svc;
@@ -42,7 +49,7 @@ beforeEach(() => {
   vi.clearAllMocks();
   existsSync.mockReturnValue(false);
   readdirSync.mockReturnValue([]);
-  execSync.mockImplementation(() => { throw new Error('command not found'); });
+  execFileSync.mockImplementation(() => { throw new Error('command not found'); });
 });
 
 describe('KitineraryExtractorService binary probe', () => {
@@ -79,9 +86,41 @@ describe('KitineraryExtractorService binary probe', () => {
     await expect(boot().extract(Buffer.from(''), 'x.pdf')).rejects.toThrow('not available');
   });
 
-  it('KIT-EXT-007: falls back to the binary on PATH when nothing is on disk', () => {
-    execSync.mockReturnValue(Buffer.from(''));
-    expect(boot().isAvailable()).toBe(true);
-    expect(execSync).toHaveBeenCalledWith('kitinerary-extractor --version', expect.objectContaining({ timeout: 3000 }));
+  it('KIT-EXT-007: falls back to a binary on the search path when nothing is on disk', () => {
+    existsSync.mockImplementation((p: string) => p === onPath('/usr/local/bin'));
+    execFileSync.mockReturnValue(Buffer.from(''));
+
+    expect(boot({ searchPath: ['/usr/local/bin'] }).isAvailable()).toBe(true);
+    expect(execFileSync).toHaveBeenCalledWith(
+      onPath('/usr/local/bin'), ['--version'], expect.objectContaining({ timeout: 3000 }),
+    );
+  });
+
+  it('KIT-EXT-008: stores the absolute path, never the bare name', async () => {
+    existsSync.mockImplementation((p: string) => p === onPath('/opt/tools'));
+    execFileSync.mockReturnValue(Buffer.from(''));
+    execFile.mockImplementation((_b: string, _a: string[], _o: unknown, cb: (e: null, r: unknown) => void) =>
+      cb(null, { stdout: '[]', stderr: '' }));
+
+    // An unqualified name would be re-resolved through PATH on every extraction,
+    // so what the probe stores has to be the concrete file it verified.
+    await boot({ searchPath: ['/opt/tools'] }).extract(Buffer.from(''), 'x.pdf');
+
+    expect(execFile).toHaveBeenCalledWith(
+      onPath('/opt/tools'), [expect.any(String)], expect.anything(), expect.anything(),
+    );
+  });
+
+  it('KIT-EXT-009: a search-path entry that exists but will not run is skipped', () => {
+    existsSync.mockReturnValue(true);
+    execFileSync.mockImplementation((bin: string) => {
+      if (bin === onPath('/broken')) throw new Error('not executable');
+      return Buffer.from('');
+    });
+
+    expect(boot({ searchPath: ['/broken', '/good'] }).isAvailable()).toBe(true);
+    expect(execFileSync).toHaveBeenLastCalledWith(
+      onPath('/good'), ['--version'], expect.anything(),
+    );
   });
 });
diff --git a/sonar-project.properties b/sonar-project.properties
index ae3b3511c..226053367 100644
--- a/sonar-project.properties
+++ b/sonar-project.properties
@@ -62,10 +62,86 @@ sonar.cpd.exclusions=shared/src/i18n/**
 # Locale files are UI copy — strings like "Password", "API key", "token" are labels,
 # not credentials, and the secret detectors false-positive on them constantly.
 # Ignore the secrets analyzer and the hard-coded-credential rules on i18n only.
-sonar.issue.ignore.multicriteria=i18nsec1,i18nsec2,i18nsec3
+sonar.issue.ignore.multicriteria=i18nsec1,i18nsec2,i18nsec3,rand1,rand2,rand3,rand4,rand5,cli1,hash1,hash2,hash3,hash4,ns1,ns2,frame1
 sonar.issue.ignore.multicriteria.i18nsec1.ruleKey=secrets:*
 sonar.issue.ignore.multicriteria.i18nsec1.resourceKey=shared/src/i18n/**
 sonar.issue.ignore.multicriteria.i18nsec2.ruleKey=typescript:S2068
 sonar.issue.ignore.multicriteria.i18nsec2.resourceKey=shared/src/i18n/**
 sonar.issue.ignore.multicriteria.i18nsec3.ruleKey=typescript:S6418
 sonar.issue.ignore.multicriteria.i18nsec3.resourceKey=shared/src/i18n/**
+
+# S2245 (Math.random in a security context) — scoped per file, never globally, so
+# a future Math.random() on an auth, token or crypto path still fails the gate.
+# The two places where the value DID reach something that matters — the two
+# idempotency-key producers — were fixed instead of listed here; they now share
+# client/src/utils/randomId.ts.
+#
+# Studio + studioStore: element and spread ids inside a photo-book document. The
+# whole document is stored and fetched as one blob scoped by journey id, so an
+# element id is never a URL, a lookup key or an authorization subject. Worst case
+# of a collision is documented in studioStore itself: two elements would share a
+# selection.
+sonar.issue.ignore.multicriteria.rand1.ruleKey=typescript:S2245
+sonar.issue.ignore.multicriteria.rand1.resourceKey=client/src/components/Studio/**
+sonar.issue.ignore.multicriteria.rand2.ruleKey=typescript:S2245
+sonar.issue.ignore.multicriteria.rand2.resourceKey=client/src/store/studioStore.ts
+# LoginWorld: canvas animation parameters — arc endpoints, flight speed, spawn
+# delays. Nothing crosses a trust boundary; nothing leaves the browser.
+sonar.issue.ignore.multicriteria.rand3.ruleKey=typescript:S2245
+sonar.issue.ignore.multicriteria.rand3.resourceKey=client/src/pages/login/LoginWorld.tsx
+# placesSession: a Google Places session token. It is a BILLING correlator, not a
+# credential — Google groups requests by (API key, token) for pricing. Suggestions
+# derive from the typed input, never from the token, so a guessed value cannot
+# pull another user's results. The Math.random rung is also the third fallback,
+# reached only where Web Crypto is absent entirely.
+sonar.issue.ignore.multicriteria.rand4.ruleKey=typescript:S2245
+sonar.issue.ignore.multicriteria.rand4.resourceKey=client/src/utils/placesSession.ts
+# Cost-split rows: React list keys for ephemeral ticket rows, dropped before the
+# payload is serialised (see writeTicketItems) so they never reach the API or DB.
+sonar.issue.ignore.multicriteria.rand5.ruleKey=typescript:S2245
+sonar.issue.ignore.multicriteria.rand5.resourceKey=client/src/components/Budget/CostsPanel.tsx
+sonar.issue.ignore.multicriteria.cli1.ruleKey=typescript:S2245
+sonar.issue.ignore.multicriteria.cli1.resourceKey=client/src/mobile/screens/trip/sheets/MCostSheet.tsx
+
+# S4790 (weak hash) — every one of these derives a cache key or a filename, never
+# a token, signature or integrity check, and the digest never reaches a client:
+# the public URLs carry the plain placeId/photoId. Every genuine security hash in
+# the server is already sha256 (backup codes, tokens, PKCE, the plugin audit
+# chain). Swapping these would only orphan existing cached files — thumbnail.ts
+# says so in its own comment.
+sonar.issue.ignore.multicriteria.hash1.ruleKey=typescript:S4790
+sonar.issue.ignore.multicriteria.hash1.resourceKey=server/src/nest/memories/**
+sonar.issue.ignore.multicriteria.hash2.ruleKey=typescript:S4790
+sonar.issue.ignore.multicriteria.hash2.resourceKey=server/src/nest/place-photos/**
+sonar.issue.ignore.multicriteria.hash3.ruleKey=typescript:S4790
+sonar.issue.ignore.multicriteria.hash3.resourceKey=server/src/nest/place-enrichment/**
+
+# S4036 (OS command via PATH) — the plugin SDK is a CLI a plugin author runs on
+# their own machine, and reaching git/npm through the developer's own PATH is the
+# point of it. Every invocation passes an argv array, so nothing is shell-parsed.
+# The one server-side site was NOT suppressed: it now resolves its binary to an
+# absolute path (see kitinerary-extractor.service.ts).
+sonar.issue.ignore.multicriteria.hash4.ruleKey=typescript:S4036
+sonar.issue.ignore.multicriteria.hash4.resourceKey=plugin-sdk/src/cli/**
+
+# S5332 (clear-text protocol) — neither site opens a connection.
+# gpx-export: the GPX and XSI namespace URIs plus the schemaLocation pair. A
+# namespace is an exact identifier fixed by the schema, so rewriting it to
+# https:// would produce GPX that other tools reject.
+sonar.issue.ignore.multicriteria.ns1.ruleKey=typescript:S5332
+sonar.issue.ignore.multicriteria.ns1.resourceKey=server/src/nest/places/gpx-export.helpers.ts
+# host-surface: 'http://x.invalid' is a throwaway base handed to new URL() so a
+# relative path can be parsed — the very next line rejects the value if it
+# resolved anywhere else. The string is part of the guard, not a destination, and
+# .invalid is reserved by RFC 2606 precisely so it can never resolve.
+sonar.issue.ignore.multicriteria.ns2.ruleKey=typescript:S5332
+sonar.issue.ignore.multicriteria.ns2.resourceKey=server/src/nest/plugins/host/rpc/host-surface.rpc.ts
+
+# S2819 (postMessage target origin) — the plugin frame is embedded with
+# sandbox="allow-scripts allow-forms" and deliberately WITHOUT allow-same-origin,
+# so the document inside has an opaque origin. There is no origin string that
+# would match it: '*' is the only value that works, which makes the rule
+# unsatisfiable here rather than unsatisfied. The receiving side authenticates on
+# event.source instead.
+sonar.issue.ignore.multicriteria.frame1.ruleKey=typescript:S2819
+sonar.issue.ignore.multicriteria.frame1.resourceKey=client/src/components/Plugins/PluginFrame.tsx