feat: complete offline write support with mutation queue + runtime SW cache config

- Add offline CRUD to todoRepo, budgetRepo, reservationRepo, accommodationRepo,
  dayRepo, tripRepo, fileRepo with optimistic Dexie writes and mutation queue
- Wire all store slices (todo, budget, reservations, files, dayNotes, assignments,
  tripStore) through repos for offline-aware writes
- Cover archive/unarchive, file toggleStar/update/delete, assignment create/delete,
  day title/notes update offline paths
- Migrate service worker from generateSW to injectManifest (custom sw.ts) with
  runtime-configurable api-data (7d/500) and map-tiles (30d/1000) cache policies
- Add Settings → Offline cache configuration UI with save/reset and live SW postMessage
- Extend mutationQueue flush to cover all writable Dexie tables

client/src/components/Settings/OfflineTab.tsx

@@ -1,13 +1,21 @@
 /**
  * Offline settings tab — shows cached trips, storage info, and controls
- * to re-sync or clear the offline cache.
+ * to re-sync or clear the offline cache. Also exposes runtime SW cache config.
  */
-import React, { useState, useEffect, useCallback } from 'react'
-import { Wifi, RefreshCw, Trash2, Database } from 'lucide-react'
+import React, { useState, useEffect, useCallback, useRef } from 'react'
+import { Wifi, RefreshCw, Trash2, Database, Settings2, RotateCcw, CheckCircle } from 'lucide-react'
 import Section from './Section'
 import { offlineDb, clearAll } from '../../db/offlineDb'
 import { tripSyncManager } from '../../sync/tripSyncManager'
 import { mutationQueue } from '../../sync/mutationQueue'
+import {
+  DEFAULT_SW_CONFIG,
+  loadSwConfig,
+  saveSwConfig,
+  validateSwConfig,
+  SW_CONFIG_BOUNDS,
+  type SwCacheConfig,
+} from '../../sync/swConfig'
 import type { SyncMeta } from '../../db/offlineDb'
 import type { Trip } from '../../types'
 
@@ -25,6 +33,12 @@ export default function OfflineTab(): React.ReactElement {
   const [clearing, setClearing] = useState(false)
   const [loading, setLoading] = useState(true)
 
+  // Cache config state
+  const [cacheConfig, setCacheConfig] = useState<SwCacheConfig>({ ...DEFAULT_SW_CONFIG })
+  const [configSaving, setConfigSaving] = useState(false)
+  const [configApplied, setConfigApplied] = useState<Date | null>(null)
+  const appliedTimerRef = useRef<ReturnType<typeof setTimeout> | null>(null)
+
   const load = useCallback(async () => {
     setLoading(true)
     try {
@@ -53,6 +67,59 @@ export default function OfflineTab(): React.ReactElement {
 
   useEffect(() => { load() }, [load])
 
+  // Load persisted cache config on mount
+  useEffect(() => {
+    loadSwConfig().then(setCacheConfig).catch(() => {})
+  }, [])
+
+  // Listen for SW acknowledgement
+  useEffect(() => {
+    const handler = (event: MessageEvent) => {
+      if (event.data?.type === 'CACHE_CONFIG_APPLIED') {
+        setConfigApplied(new Date())
+        setConfigSaving(false)
+        if (appliedTimerRef.current) clearTimeout(appliedTimerRef.current)
+        appliedTimerRef.current = setTimeout(() => setConfigApplied(null), 5000)
+      }
+    }
+    navigator.serviceWorker?.addEventListener('message', handler)
+    return () => {
+      navigator.serviceWorker?.removeEventListener('message', handler)
+      if (appliedTimerRef.current) clearTimeout(appliedTimerRef.current)
+    }
+  }, [])
+
+  async function handleSaveConfig() {
+    const validated = validateSwConfig(cacheConfig)
+    setCacheConfig(validated)
+    setConfigSaving(true)
+    try {
+      await saveSwConfig(validated)
+      const controller = navigator.serviceWorker?.controller
+      if (controller) {
+        controller.postMessage({ type: 'UPDATE_CACHE_CONFIG', config: validated })
+        // configSaving cleared by the SW message handler
+      } else {
+        // No active SW yet (e.g. first install) — config saved to IDB, applied on next SW activation
+        setConfigApplied(new Date())
+        setConfigSaving(false)
+      }
+    } catch {
+      setConfigSaving(false)
+    }
+  }
+
+  function handleResetConfig() {
+    setCacheConfig({ ...DEFAULT_SW_CONFIG })
+  }
+
+  function updateField(field: keyof SwCacheConfig) {
+    return (e: React.ChangeEvent<HTMLInputElement>) => {
+      const v = parseInt(e.target.value, 10)
+      if (!isNaN(v)) setCacheConfig(prev => ({ ...prev, [field]: v }))
+    }
+  }
+
   async function handleResync() {
     setSyncing(true)
     try {
@@ -120,6 +187,86 @@ export default function OfflineTab(): React.ReactElement {
           </button>
         </div>
 
+        {/* Cache configuration */}
+        <div style={{ display: 'flex', flexDirection: 'column', gap: 12 }}>
+          <div style={{ display: 'flex', alignItems: 'center', gap: 6 }}>
+            <Settings2 size={14} style={{ color: 'var(--text-muted)' }} />
+            <span style={{ fontSize: 13, fontWeight: 600, color: 'var(--text-primary)' }}>Cache configuration</span>
+          </div>
+          <p style={{ fontSize: 12, color: 'var(--text-muted)', margin: 0 }}>
+            Changes apply immediately to the service worker and persist across reloads.
+            Existing cached entries follow their original TTL; new entries use the updated settings.
+          </p>
+
+          <div style={{ display: 'grid', gridTemplateColumns: '1fr 1fr', gap: 8 }}>
+            <CacheField
+              label="API cache TTL (days)"
+              value={cacheConfig.apiTtlDays}
+              min={SW_CONFIG_BOUNDS.ttlMin}
+              max={SW_CONFIG_BOUNDS.ttlMax}
+              onChange={updateField('apiTtlDays')}
+            />
+            <CacheField
+              label="API max entries"
+              value={cacheConfig.apiMaxEntries}
+              min={SW_CONFIG_BOUNDS.entriesMin}
+              max={SW_CONFIG_BOUNDS.entriesMax}
+              onChange={updateField('apiMaxEntries')}
+            />
+            <CacheField
+              label="Map tiles TTL (days)"
+              value={cacheConfig.tilesTtlDays}
+              min={SW_CONFIG_BOUNDS.ttlMin}
+              max={SW_CONFIG_BOUNDS.ttlMax}
+              onChange={updateField('tilesTtlDays')}
+            />
+            <CacheField
+              label="Map tiles max entries"
+              value={cacheConfig.tilesMaxEntries}
+              min={SW_CONFIG_BOUNDS.entriesMin}
+              max={SW_CONFIG_BOUNDS.entriesMax}
+              onChange={updateField('tilesMaxEntries')}
+            />
+          </div>
+
+          <div style={{ display: 'flex', alignItems: 'center', gap: 8, flexWrap: 'wrap' }}>
+            <button
+              onClick={handleSaveConfig}
+              disabled={configSaving}
+              style={{
+                display: 'flex', alignItems: 'center', gap: 6, padding: '8px 14px',
+                borderRadius: 8, border: '1px solid var(--border-primary)',
+                background: 'var(--bg-secondary)', color: 'var(--text-primary)',
+                cursor: configSaving ? 'not-allowed' : 'pointer',
+                fontSize: 13, fontWeight: 500, opacity: configSaving ? 0.6 : 1,
+              }}
+            >
+              <RefreshCw size={14} style={configSaving ? { animation: 'spin 1s linear infinite' } : {}} />
+              {configSaving ? 'Applying…' : 'Save'}
+            </button>
+            <button
+              onClick={handleResetConfig}
+              disabled={configSaving}
+              style={{
+                display: 'flex', alignItems: 'center', gap: 6, padding: '8px 14px',
+                borderRadius: 8, border: '1px solid var(--border-primary)',
+                background: 'var(--bg-secondary)', color: 'var(--text-muted)',
+                cursor: configSaving ? 'not-allowed' : 'pointer',
+                fontSize: 13, fontWeight: 500,
+              }}
+            >
+              <RotateCcw size={14} />
+              Reset to defaults
+            </button>
+            {configApplied && (
+              <span style={{ display: 'flex', alignItems: 'center', gap: 4, fontSize: 12, color: '#22c55e' }}>
+                <CheckCircle size={12} />
+                Applied at {configApplied.toLocaleTimeString(undefined, { hour: '2-digit', minute: '2-digit' })}
+              </span>
+            )}
+          </div>
+        </div>
+
         {/* Cached trip list */}
         {loading ? (
           <p style={{ color: 'var(--text-muted)', fontSize: 13 }}>Loading…</p>
@@ -139,24 +286,32 @@ export default function OfflineTab(): React.ReactElement {
                   display: 'flex', flexDirection: 'column', gap: 2,
                 }}
               >
-                <div style={{ display: 'flex', justifyContent: 'space-between', alignItems: 'center' }}>
-                  <span style={{ fontWeight: 600, fontSize: 14, color: 'var(--text-primary)' }}>
-                    {trip.name}
-                  </span>
-                  <span style={{ fontSize: 11, color: 'var(--text-muted)' }}>
+                <div style={{ display: 'flex', justifyContent: 'space-between', alignItems: 'flex-start', gap: 8 }}>
+                  <div style={{ display: 'flex', flexDirection: 'column', gap: 2, minWidth: 0 }}>
+                    <span style={{ fontWeight: 600, fontSize: 14, color: trip.title ? 'var(--text-primary)' : 'var(--text-muted)', fontStyle: trip.title ? 'normal' : 'italic', overflow: 'hidden', textOverflow: 'ellipsis', whiteSpace: 'nowrap' }}>
+                      {trip.title || 'Unnamed trip'}
+                    </span>
+                    {trip.description ? (
+                      <span style={{ fontSize: 11, color: 'var(--text-muted)', overflow: 'hidden', textOverflow: 'ellipsis', whiteSpace: 'nowrap' }}>
+                        {trip.description.length > 72 ? trip.description.slice(0, 72) + '…' : trip.description}
+                      </span>
+                    ) : null}
+                    <span style={{ fontSize: 11, color: 'var(--text-muted)' }}>
+                      {trip.start_date
+                        ? `${formatDate(trip.start_date)} – ${formatDate(trip.end_date)}`
+                        : 'No dates set'}
+                      {' · '}
+                      {placeCount} place{placeCount !== 1 ? 's' : ''}
+                      {fileCount > 0 ? ` · ${fileCount} file${fileCount !== 1 ? 's' : ''}` : null}
+                    </span>
+                  </div>
+                  <span style={{ fontSize: 11, color: 'var(--text-muted)', whiteSpace: 'nowrap', flexShrink: 0 }}>
                     <Wifi size={10} style={{ display: 'inline', marginRight: 3 }} />
                     {meta.lastSyncedAt
                       ? new Date(meta.lastSyncedAt).toLocaleTimeString(undefined, { hour: '2-digit', minute: '2-digit' })
                       : '—'}
                   </span>
                 </div>
-                <span style={{ fontSize: 12, color: 'var(--text-muted)' }}>
-                  {formatDate(trip.start_date)} – {formatDate(trip.end_date)}
-                  {' · '}
-                  {placeCount} place{placeCount !== 1 ? 's' : ''}
-                  {' · '}
-                  {fileCount} file{fileCount !== 1 ? 's' : ''}
-                </span>
               </div>
             ))}
           </div>
@@ -178,3 +333,32 @@ function Stat({ label, value }: { label: string; value: number }) {
     </div>
   )
 }
+
+function CacheField({
+  label, value, min, max, onChange,
+}: {
+  label: string
+  value: number
+  min: number
+  max: number
+  onChange: (e: React.ChangeEvent<HTMLInputElement>) => void
+}) {
+  return (
+    <label style={{ display: 'flex', flexDirection: 'column', gap: 4 }}>
+      <span style={{ fontSize: 11, color: 'var(--text-muted)', fontWeight: 500 }}>{label}</span>
+      <input
+        type="number"
+        value={value}
+        min={min}
+        max={max}
+        onChange={onChange}
+        style={{
+          padding: '6px 10px', borderRadius: 6,
+          border: '1px solid var(--border-primary)',
+          background: 'var(--bg-secondary)', color: 'var(--text-primary)',
+          fontSize: 13, width: '100%', boxSizing: 'border-box',
+        }}
+      />
+    </label>
+  )
+}