feat(admin): add admin-configurable default user settings

Allow admins to set instance-wide defaults for temperature unit, color
mode, time format, route calculation, blur booking codes, and map tile
URL via a new Admin > User Defaults tab. Defaults are stored in
app_settings (prefixed default_user_setting_*) and applied at read time
as a fallback — user's own explicit values always take priority.
Translations added for all 16 supported languages.

client/src/api/client.ts

@@ -299,6 +299,8 @@ export const adminApi = {
     apiClient.post('/admin/dev/test-notification', data).then(r => r.data),
   getNotificationPreferences: () => apiClient.get('/admin/notification-preferences').then(r => r.data),
   updateNotificationPreferences: (prefs: Record<string, Record<string, boolean>>) => apiClient.put('/admin/notification-preferences', prefs).then(r => r.data),
+  getDefaultUserSettings: () => apiClient.get('/admin/default-user-settings').then(r => r.data),
+  updateDefaultUserSettings: (settings: Record<string, unknown>) => apiClient.put('/admin/default-user-settings', settings).then(r => r.data),
 }
 
 export const addonsApi = {

client/src/components/Admin/DefaultUserSettingsTab.tsx

@@ -0,0 +1,248 @@
+import React, { useEffect, useState } from 'react'
+import { Settings2 } from 'lucide-react'
+import { adminApi } from '../../api/client'
+import { useTranslation } from '../../i18n'
+import { useToast } from '../shared/Toast'
+import Section from '../Settings/Section'
+import CustomSelect from '../shared/CustomSelect'
+
+const MAP_PRESETS = [
+  { name: 'OpenStreetMap', url: 'https://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png' },
+  { name: 'OpenStreetMap DE', url: 'https://tile.openstreetmap.de/{z}/{x}/{y}.png' },
+  { name: 'CartoDB Light', url: 'https://{s}.basemaps.cartocdn.com/light_all/{z}/{x}/{y}{r}.png' },
+  { name: 'CartoDB Dark', url: 'https://{s}.basemaps.cartocdn.com/dark_all/{z}/{x}/{y}{r}.png' },
+  { name: 'Stadia Smooth', url: 'https://tiles.stadiamaps.com/tiles/alidade_smooth/{z}/{x}/{y}{r}.png' },
+]
+
+type Defaults = {
+  temperature_unit?: string
+  dark_mode?: string | boolean
+  time_format?: string
+  route_calculation?: boolean
+  blur_booking_codes?: boolean
+  map_tile_url?: string
+}
+
+function OptionRow({
+  label,
+  hint,
+  children,
+}: {
+  label: React.ReactNode
+  hint?: string
+  children: React.ReactNode
+}) {
+  return (
+    <div>
+      <label className="block text-sm font-medium mb-2" style={{ color: 'var(--text-secondary)' }}>
+        {label}
+      </label>
+      {hint && <p className="text-xs mb-2" style={{ color: 'var(--text-faint)' }}>{hint}</p>}
+      <div className="flex gap-3 flex-wrap">{children}</div>
+    </div>
+  )
+}
+
+function OptionButton({
+  active,
+  onClick,
+  children,
+}: {
+  active: boolean
+  onClick: () => void
+  children: React.ReactNode
+}) {
+  return (
+    <button
+      onClick={onClick}
+      style={{
+        display: 'flex', alignItems: 'center', gap: 8,
+        padding: '10px 20px', borderRadius: 10, cursor: 'pointer',
+        fontFamily: 'inherit', fontSize: 14, fontWeight: 500,
+        border: active ? '2px solid var(--text-primary)' : '2px solid var(--border-primary)',
+        background: active ? 'var(--bg-hover)' : 'var(--bg-card)',
+        color: 'var(--text-primary)',
+        transition: 'all 0.15s',
+      }}
+    >
+      {children}
+    </button>
+  )
+}
+
+export default function DefaultUserSettingsTab(): React.ReactElement {
+  const { t } = useTranslation()
+  const toast = useToast()
+  const [defaults, setDefaults] = useState<Defaults>({})
+  const [loaded, setLoaded] = useState(false)
+  const [mapTileUrl, setMapTileUrl] = useState('')
+
+  useEffect(() => {
+    adminApi.getDefaultUserSettings().then((data: Defaults) => {
+      setDefaults(data)
+      setMapTileUrl(data.map_tile_url || '')
+      setLoaded(true)
+    }).catch(() => setLoaded(true))
+  }, [])
+
+  const save = async (patch: Partial<Defaults>) => {
+    try {
+      const updated = await adminApi.updateDefaultUserSettings(patch as Record<string, unknown>)
+      setDefaults(updated)
+      toast.success(t('admin.defaultSettings.saved'))
+    } catch (err: unknown) {
+      toast.error(err instanceof Error ? err.message : t('common.error'))
+    }
+  }
+
+  const reset = async (key: keyof Defaults) => {
+    try {
+      const updated = await adminApi.updateDefaultUserSettings({ [key]: null })
+      setDefaults(updated)
+      if (key === 'map_tile_url') setMapTileUrl('')
+      toast.success(t('admin.defaultSettings.reset'))
+    } catch (err: unknown) {
+      toast.error(err instanceof Error ? err.message : t('common.error'))
+    }
+  }
+
+  const isSet = (key: keyof Defaults) => defaults[key] !== undefined
+
+  const ResetButton = ({ field }: { field: keyof Defaults }) =>
+    isSet(field) ? (
+      <button
+        onClick={() => reset(field)}
+        className="text-xs ml-2"
+        style={{ color: 'var(--text-faint)', textDecoration: 'underline', background: 'none', border: 'none', cursor: 'pointer' }}
+      >
+        {t('admin.defaultSettings.resetToBuiltIn')}
+      </button>
+    ) : null
+
+  if (!loaded) {
+    return <p style={{ fontSize: 12, color: 'var(--text-faint)', fontStyle: 'italic', padding: 16 }}>Loading…</p>
+  }
+
+  const darkMode = defaults.dark_mode
+
+  return (
+    <Section title={t('admin.defaultSettings.title')} icon={Settings2}>
+      <p className="text-sm" style={{ color: 'var(--text-faint)', marginTop: -8 }}>
+        {t('admin.defaultSettings.description')}
+      </p>
+
+      {/* Color Mode */}
+      <OptionRow label={<>{t('settings.colorMode')} <ResetButton field="dark_mode" /></>}>
+        {([
+          { value: 'light', label: t('settings.light') },
+          { value: 'dark', label: t('settings.dark') },
+          { value: 'auto', label: t('settings.auto') },
+        ] as const).map(opt => (
+          <OptionButton
+            key={opt.value}
+            active={darkMode === opt.value || (opt.value === 'light' && darkMode === false) || (opt.value === 'dark' && darkMode === true)}
+            onClick={() => save({ dark_mode: opt.value })}
+          >
+            {opt.label}
+          </OptionButton>
+        ))}
+      </OptionRow>
+
+      {/* Temperature */}
+      <OptionRow label={<>{t('settings.temperature')} <ResetButton field="temperature_unit" /></>}>
+        {([
+          { value: 'celsius', label: '°C Celsius' },
+          { value: 'fahrenheit', label: '°F Fahrenheit' },
+        ] as const).map(opt => (
+          <OptionButton
+            key={opt.value}
+            active={defaults.temperature_unit === opt.value}
+            onClick={() => save({ temperature_unit: opt.value })}
+          >
+            {opt.label}
+          </OptionButton>
+        ))}
+      </OptionRow>
+
+      {/* Time Format */}
+      <OptionRow label={<>{t('settings.timeFormat')} <ResetButton field="time_format" /></>}>
+        {([
+          { value: '24h', label: '24h (14:30)' },
+          { value: '12h', label: '12h (2:30 PM)' },
+        ] as const).map(opt => (
+          <OptionButton
+            key={opt.value}
+            active={defaults.time_format === opt.value}
+            onClick={() => save({ time_format: opt.value })}
+          >
+            {opt.label}
+          </OptionButton>
+        ))}
+      </OptionRow>
+
+      {/* Route Calculation */}
+      <OptionRow label={<>{t('settings.routeCalculation')} <ResetButton field="route_calculation" /></>}>
+        {([
+          { value: true, label: t('settings.on') || 'On' },
+          { value: false, label: t('settings.off') || 'Off' },
+        ] as const).map(opt => (
+          <OptionButton
+            key={String(opt.value)}
+            active={defaults.route_calculation === opt.value}
+            onClick={() => save({ route_calculation: opt.value })}
+          >
+            {opt.label}
+          </OptionButton>
+        ))}
+      </OptionRow>
+
+      {/* Blur Booking Codes */}
+      <OptionRow label={<>{t('settings.blurBookingCodes')} <ResetButton field="blur_booking_codes" /></>}>
+        {([
+          { value: true, label: t('settings.on') || 'On' },
+          { value: false, label: t('settings.off') || 'Off' },
+        ] as const).map(opt => (
+          <OptionButton
+            key={String(opt.value)}
+            active={defaults.blur_booking_codes === opt.value}
+            onClick={() => save({ blur_booking_codes: opt.value })}
+          >
+            {opt.label}
+          </OptionButton>
+        ))}
+      </OptionRow>
+
+      {/* Map Tile URL */}
+      <div>
+        <label className="block text-sm font-medium mb-1.5" style={{ color: 'var(--text-secondary)' }}>
+          {t('settings.mapTemplate')}
+          <ResetButton field="map_tile_url" />
+        </label>
+        <CustomSelect
+          value={mapTileUrl}
+          onChange={(value: string) => { if (value) setMapTileUrl(value) }}
+          placeholder={t('settings.mapTemplatePlaceholder.select')}
+          options={MAP_PRESETS.map(p => ({ value: p.url, label: p.name }))}
+          size="sm"
+          style={{ marginBottom: 8 }}
+        />
+        <div className="flex gap-2 items-center">
+          <input
+            type="text"
+            value={mapTileUrl}
+            onChange={(e: React.ChangeEvent<HTMLInputElement>) => setMapTileUrl(e.target.value)}
+            placeholder="https://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png"
+            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
+            onClick={() => save({ map_tile_url: mapTileUrl })}
+            className="px-4 py-2 bg-slate-900 text-white rounded-lg text-sm hover:bg-slate-700 whitespace-nowrap"
+          >
+            {t('common.save')}
+          </button>
+        </div>
+        <p className="text-xs mt-1" style={{ color: 'var(--text-faint)' }}>{t('settings.mapDefaultHint')}</p>
+      </div>
+    </Section>
+  )
+}

client/src/i18n/translations/ar.ts

@@ -464,6 +464,12 @@ const ar: Record<string, string | { name: string; category: string }[]> = {
   'admin.tabs.audit': 'تدقيق',
   'admin.tabs.settings': 'الإعدادات',
   'admin.tabs.config': 'التخصيص',
+  'admin.tabs.defaults': 'الإعدادات الافتراضية',
+  'admin.defaultSettings.title': 'إعدادات المستخدم الافتراضية',
+  'admin.defaultSettings.description': 'تعيين الإعدادات الافتراضية على مستوى النظام. سيرى المستخدمون الذين لم يغيروا إعدادًا هذه القيم. تحظى تغييراتهم دائمًا بالأولوية.',
+  'admin.defaultSettings.saved': 'تم حفظ الإعداد الافتراضي',
+  'admin.defaultSettings.reset': 'إعادة التعيين إلى الإعداد الافتراضي المدمج',
+  'admin.defaultSettings.resetToBuiltIn': 'إعادة تعيين',
   'admin.tabs.templates': 'قوالب التعبئة',
   'admin.tabs.addons': 'الإضافات',
   'admin.tabs.mcpTokens': 'وصول MCP',

client/src/i18n/translations/br.ts

@@ -549,6 +549,12 @@ const br: Record<string, string | { name: string; category: string }[]> = {
   'admin.bagTracking.title': 'Rastreamento de malas',
   'admin.bagTracking.subtitle': 'Ativar peso e atribuição de mala para itens da lista',
   'admin.tabs.config': 'Personalização',
+  'admin.tabs.defaults': 'Padrões do usuário',
+  'admin.defaultSettings.title': 'Configurações padrão do usuário',
+  'admin.defaultSettings.description': 'Defina padrões para toda a instância. Usuários que não alteraram uma configuração verão esses valores. As próprias alterações deles sempre têm prioridade.',
+  'admin.defaultSettings.saved': 'Padrão salvo',
+  'admin.defaultSettings.reset': 'Redefinir para o padrão integrado',
+  'admin.defaultSettings.resetToBuiltIn': 'redefinir',
   'admin.tabs.templates': 'Modelos de mala',
   'admin.packingTemplates.title': 'Modelos de mala',
   'admin.packingTemplates.subtitle': 'Crie listas de mala reutilizáveis para suas viagens',

client/src/i18n/translations/cs.ts

@@ -549,6 +549,12 @@ const cs: Record<string, string | { name: string; category: string }[]> = {
   'admin.bagTracking.title': 'Sledování zavazadel',
   'admin.bagTracking.subtitle': 'Povolit váhu a přiřazení k zavazadlům u položek balení',
   'admin.tabs.config': 'Personalizace',
+  'admin.tabs.defaults': 'Výchozí nastavení uživatele',
+  'admin.defaultSettings.title': 'Výchozí nastavení uživatele',
+  'admin.defaultSettings.description': 'Nastavte výchozí hodnoty pro celou instanci. Uživatelé, kteří nezměnili nastavení, uvidí tyto hodnoty. Jejich vlastní změny mají vždy přednost.',
+  'admin.defaultSettings.saved': 'Výchozí nastavení uloženo',
+  'admin.defaultSettings.reset': 'Obnovit na vestavěnou výchozí hodnotu',
+  'admin.defaultSettings.resetToBuiltIn': 'obnovit',
   'admin.tabs.templates': 'Šablony seznamů',
   'admin.packingTemplates.title': 'Šablony pro balení',
   'admin.packingTemplates.subtitle': 'Vytvářejte opakovaně použitelné seznamy pro své cesty',

client/src/i18n/translations/de.ts

@@ -553,6 +553,12 @@ const de: Record<string, string | { name: string; category: string }[]> = {
   'admin.bagTracking.title': 'Gepäck-Tracking',
   'admin.bagTracking.subtitle': 'Gewicht und Gepäckstück-Zuordnung für Packlisteneinträge aktivieren',
   'admin.tabs.config': 'Personalisierung',
+  'admin.tabs.defaults': 'Benutzer-Standards',
+  'admin.defaultSettings.title': 'Standard-Benutzereinstellungen',
+  'admin.defaultSettings.description': 'Instanzweite Standards festlegen. Benutzer, die eine Einstellung nicht geändert haben, sehen diese Werte. Eigene Änderungen haben immer Vorrang.',
+  'admin.defaultSettings.saved': 'Standard gespeichert',
+  'admin.defaultSettings.reset': 'Auf eingebauten Standard zurücksetzen',
+  'admin.defaultSettings.resetToBuiltIn': 'zurücksetzen',
   'admin.tabs.templates': 'Packvorlagen',
   'admin.packingTemplates.title': 'Packvorlagen',
   'admin.packingTemplates.subtitle': 'Wiederverwendbare Packlisten für deine Reisen erstellen',

client/src/i18n/translations/en.ts

@@ -609,6 +609,12 @@ const en: Record<string, string | { name: string; category: string }[]> = {
   'admin.bagTracking.title': 'Bag Tracking',
   'admin.bagTracking.subtitle': 'Enable weight and bag assignment for packing items',
   'admin.tabs.config': 'Personalization',
+  'admin.tabs.defaults': 'User Defaults',
+  'admin.defaultSettings.title': 'Default User Settings',
+  'admin.defaultSettings.description': 'Set instance-wide defaults. Users who have not changed a setting will see these values. Their own changes always take priority.',
+  'admin.defaultSettings.saved': 'Default saved',
+  'admin.defaultSettings.reset': 'Reset to built-in default',
+  'admin.defaultSettings.resetToBuiltIn': 'reset',
   'admin.tabs.templates': 'Packing Templates',
   'admin.packingTemplates.title': 'Packing Templates',
   'admin.packingTemplates.subtitle': 'Create reusable packing lists for your trips',

client/src/i18n/translations/es.ts

@@ -544,6 +544,12 @@ const es: Record<string, string> = {
   'admin.bagTracking.title': 'Seguimiento de equipaje',
   'admin.bagTracking.subtitle': 'Activar peso y asignación de equipaje para artículos de la lista',
   'admin.tabs.config': 'Personalización',
+  'admin.tabs.defaults': 'Valores predeterminados',
+  'admin.defaultSettings.title': 'Configuración predeterminada de usuarios',
+  'admin.defaultSettings.description': 'Establece valores predeterminados para toda la instancia. Los usuarios que no hayan cambiado una opción verán estos valores. Sus propios cambios siempre tienen prioridad.',
+  'admin.defaultSettings.saved': 'Predeterminado guardado',
+  'admin.defaultSettings.reset': 'Restaurar al valor predeterminado integrado',
+  'admin.defaultSettings.resetToBuiltIn': 'restaurar',
   'admin.tabs.templates': 'Plantillas de equipaje',
   'admin.packingTemplates.title': 'Plantillas de equipaje',
   'admin.packingTemplates.subtitle': 'Crear listas de equipaje reutilizables para tus viajes',

client/src/i18n/translations/fr.ts

@@ -548,6 +548,12 @@ const fr: Record<string, string> = {
   'admin.bagTracking.title': 'Suivi des bagages',
   'admin.bagTracking.subtitle': 'Activer le poids et l\'attribution de bagages pour les articles',
   'admin.tabs.config': 'Personnalisation',
+  'admin.tabs.defaults': 'Valeurs par défaut',
+  'admin.defaultSettings.title': 'Paramètres utilisateur par défaut',
+  'admin.defaultSettings.description': "Définissez des valeurs par défaut pour toute l'instance. Les utilisateurs n'ayant pas modifié un paramètre verront ces valeurs. Leurs propres modifications ont toujours la priorité.",
+  'admin.defaultSettings.saved': 'Valeur par défaut enregistrée',
+  'admin.defaultSettings.reset': 'Réinitialiser à la valeur par défaut intégrée',
+  'admin.defaultSettings.resetToBuiltIn': 'réinitialiser',
   'admin.tabs.templates': 'Modèles de bagages',
   'admin.packingTemplates.title': 'Modèles de bagages',
   'admin.packingTemplates.subtitle': 'Créer des listes de bagages réutilisables pour vos voyages',

client/src/i18n/translations/hu.ts

@@ -549,6 +549,12 @@ const hu: Record<string, string | { name: string; category: string }[]> = {
   'admin.bagTracking.title': 'Poggyászkövetés',
   'admin.bagTracking.subtitle': 'Súly- és táskahozzárendelés engedélyezése csomagolási tételeknél',
   'admin.tabs.config': 'Személyre szabás',
+  'admin.tabs.defaults': 'Alapértelmezett beállítások',
+  'admin.defaultSettings.title': 'Alapértelmezett felhasználói beállítások',
+  'admin.defaultSettings.description': 'Állítson be alapértelmezett értékeket az egész példányra. Azok a felhasználók, akik nem módosítottak egy beállítást, ezeket az értékeket fogják látni. A saját módosításaik mindig elsőbbséget élveznek.',
+  'admin.defaultSettings.saved': 'Alapértelmezett mentve',
+  'admin.defaultSettings.reset': 'Visszaállítás a beépített alapértelmezésre',
+  'admin.defaultSettings.resetToBuiltIn': 'visszaállítás',
   'admin.tabs.templates': 'Csomagolási sablonok',
   'admin.packingTemplates.title': 'Csomagolási sablonok',
   'admin.packingTemplates.subtitle': 'Újrafelhasználható csomagolási listák létrehozása utazásaidhoz',

client/src/i18n/translations/id.ts

@@ -609,6 +609,12 @@ const id: Record<string, string | { name: string; category: string }[]> = {
   'admin.bagTracking.title': 'Pelacak Tas',
   'admin.bagTracking.subtitle': 'Aktifkan berat dan penugasan tas untuk item packing',
   'admin.tabs.config': 'Personalisasi',
+  'admin.tabs.defaults': 'Pengaturan Default Pengguna',
+  'admin.defaultSettings.title': 'Pengaturan Default Pengguna',
+  'admin.defaultSettings.description': 'Tetapkan nilai default untuk seluruh instance. Pengguna yang belum mengubah pengaturan akan melihat nilai-nilai ini. Perubahan mereka sendiri selalu diprioritaskan.',
+  'admin.defaultSettings.saved': 'Default disimpan',
+  'admin.defaultSettings.reset': 'Atur ulang ke default bawaan',
+  'admin.defaultSettings.resetToBuiltIn': 'atur ulang',
   'admin.tabs.templates': 'Template Packing',
   'admin.packingTemplates.title': 'Template Packing',
   'admin.packingTemplates.subtitle': 'Buat daftar packing yang bisa digunakan ulang untuk perjalananmu',

client/src/i18n/translations/it.ts

@@ -548,6 +548,12 @@ const it: Record<string, string | { name: string; category: string }[]> = {
   'admin.bagTracking.title': 'Tracciamento valigia',
   'admin.bagTracking.subtitle': 'Abilita il peso e l\'assegnazione della valigia per gli elementi della lista valigia',
   'admin.tabs.config': 'Personalizzazione',
+  'admin.tabs.defaults': 'Impostazioni predefinite',
+  'admin.defaultSettings.title': 'Impostazioni predefinite utente',
+  'admin.defaultSettings.description': "Imposta i valori predefiniti per l'intera istanza. Gli utenti che non hanno modificato un'impostazione vedranno questi valori. Le loro modifiche hanno sempre la priorità.",
+  'admin.defaultSettings.saved': 'Predefinito salvato',
+  'admin.defaultSettings.reset': 'Ripristina il predefinito integrato',
+  'admin.defaultSettings.resetToBuiltIn': 'ripristina',
   'admin.tabs.templates': 'Modelli lista valigia',
   'admin.packingTemplates.title': 'Modelli lista valigia',
   'admin.packingTemplates.subtitle': 'Crea liste valigia riutilizzabili per i tuoi viaggi',

client/src/i18n/translations/nl.ts

@@ -549,6 +549,12 @@ const nl: Record<string, string> = {
   'admin.bagTracking.title': 'Bagagetracking',
   'admin.bagTracking.subtitle': 'Gewicht en bagagetoewijzing inschakelen voor paklijstitems',
   'admin.tabs.config': 'Personalisatie',
+  'admin.tabs.defaults': 'Standaardinstellingen',
+  'admin.defaultSettings.title': 'Standaard gebruikersinstellingen',
+  'admin.defaultSettings.description': 'Stel instantiebrede standaardwaarden in. Gebruikers die een instelling niet hebben gewijzigd, zien deze waarden. Hun eigen wijzigingen hebben altijd voorrang.',
+  'admin.defaultSettings.saved': 'Standaard opgeslagen',
+  'admin.defaultSettings.reset': 'Terugzetten naar ingebouwde standaard',
+  'admin.defaultSettings.resetToBuiltIn': 'terugzetten',
   'admin.tabs.templates': 'Paksjablonen',
   'admin.packingTemplates.title': 'Paksjablonen',
   'admin.packingTemplates.subtitle': 'Herbruikbare paklijsten maken voor je reizen',

client/src/i18n/translations/pl.ts

@@ -521,6 +521,12 @@ const pl: Record<string, string | { name: string; category: string }[]> = {
   'admin.bagTracking.title': 'Kontrola bagażu',
   'admin.bagTracking.subtitle': 'Włącz wagę i przypisywanie do toreb dla przedmiotów do pakowania',
   'admin.tabs.config': 'Personalizacja',
+  'admin.tabs.defaults': 'Domyślne ustawienia',
+  'admin.defaultSettings.title': 'Domyślne ustawienia użytkownika',
+  'admin.defaultSettings.description': 'Ustaw domyślne wartości dla całej instancji. Użytkownicy, którzy nie zmienili ustawienia, zobaczą te wartości. Ich własne zmiany zawsze mają pierwszeństwo.',
+  'admin.defaultSettings.saved': 'Domyślne zapisane',
+  'admin.defaultSettings.reset': 'Przywróć wbudowaną wartość domyślną',
+  'admin.defaultSettings.resetToBuiltIn': 'przywróć',
   'admin.tabs.templates': 'Szablony pakowania',
   'admin.packingTemplates.title': 'Szablony pakowania',
   'admin.packingTemplates.subtitle': 'Twórz szablony list pakowania do wielokrotnego użycia dla swoich podróży',

client/src/i18n/translations/ru.ts

@@ -549,6 +549,12 @@ const ru: Record<string, string> = {
   'admin.bagTracking.title': 'Отслеживание багажа',
   'admin.bagTracking.subtitle': 'Включить вес и привязку к багажу для вещей',
   'admin.tabs.config': 'Персонализация',
+  'admin.tabs.defaults': 'Настройки по умолчанию',
+  'admin.defaultSettings.title': 'Настройки пользователей по умолчанию',
+  'admin.defaultSettings.description': 'Задайте значения по умолчанию для всего экземпляра. Пользователи, не изменившие параметр, увидят эти значения. Их собственные изменения всегда имеют приоритет.',
+  'admin.defaultSettings.saved': 'Значение по умолчанию сохранено',
+  'admin.defaultSettings.reset': 'Сбросить до встроенного значения',
+  'admin.defaultSettings.resetToBuiltIn': 'сбросить',
   'admin.tabs.templates': 'Шаблоны упаковки',
   'admin.packingTemplates.title': 'Шаблоны упаковки',
   'admin.packingTemplates.subtitle': 'Создавайте многоразовые списки вещей для поездок',

client/src/i18n/translations/zh.ts

@@ -549,6 +549,12 @@ const zh: Record<string, string> = {
   'admin.bagTracking.title': '行李追踪',
   'admin.bagTracking.subtitle': '为打包物品启用重量和行李分配',
   'admin.tabs.config': '个性化',
+  'admin.tabs.defaults': '用户默认设置',
+  'admin.defaultSettings.title': '用户默认设置',
+  'admin.defaultSettings.description': '设置实例范围的默认值。未更改设置的用户将看到这些值。用户自己的更改始终优先。',
+  'admin.defaultSettings.saved': '默认值已保存',
+  'admin.defaultSettings.reset': '重置为内置默认值',
+  'admin.defaultSettings.resetToBuiltIn': '重置',
   'admin.tabs.templates': '打包模板',
   'admin.packingTemplates.title': '打包模板',
   'admin.packingTemplates.subtitle': '创建可复用的旅行打包清单',

client/src/i18n/translations/zhTw.ts

@@ -605,6 +605,12 @@ const zhTw: Record<string, string> = {
   'admin.bagTracking.title': '行李追蹤',
   'admin.bagTracking.subtitle': '為打包物品啟用重量和行李分配',
   'admin.tabs.config': '配置',
+  'admin.tabs.defaults': '用戶預設設定',
+  'admin.defaultSettings.title': '用戶預設設定',
+  'admin.defaultSettings.description': '設定整個執行個體的預設值。未更改設定的用戶將看到這些值。用戶自己的更改始終優先。',
+  'admin.defaultSettings.saved': '預設值已儲存',
+  'admin.defaultSettings.reset': '重設為內建預設值',
+  'admin.defaultSettings.resetToBuiltIn': '重設',
   'admin.tabs.templates': '打包模板',
   'admin.packingTemplates.title': '打包模板',
   'admin.packingTemplates.subtitle': '建立可複用的旅行打包清單',

client/src/pages/AdminPage.tsx

@@ -2,6 +2,7 @@ import React, { useEffect, useState } from 'react'
 import { useNavigate } from 'react-router-dom'
 import apiClient, { adminApi, authApi, notificationsApi } from '../api/client'
 import DevNotificationsPanel from '../components/Admin/DevNotificationsPanel'
+import DefaultUserSettingsTab from '../components/Admin/DefaultUserSettingsTab'
 import { useAuthStore } from '../store/authStore'
 import { useSettingsStore } from '../store/settingsStore'
 import { useAddonStore } from '../store/addonStore'
@@ -169,6 +170,7 @@ export default function AdminPage(): React.ReactElement {
   const TABS = [
     { id: 'users', label: t('admin.tabs.users') },
     { id: 'config', label: t('admin.tabs.config') },
+    { id: 'defaults', label: t('admin.tabs.defaults') },
     { id: 'addons', label: t('admin.tabs.addons') },
     { id: 'settings', label: t('admin.tabs.settings') },
     { id: 'notifications', label: t('admin.tabs.notifications') },
@@ -1493,6 +1495,8 @@ export default function AdminPage(): React.ReactElement {
 
           {activeTab === 'github' && <GitHubPanel isPrerelease={updateInfo?.is_prerelease ?? false} />}
 
+          {activeTab === 'defaults' && <DefaultUserSettingsTab />}
+
           {activeTab === 'dev-notifications' && <DevNotificationsPanel />}
         </div>
       </div>

server/src/routes/admin.ts

@@ -3,6 +3,7 @@ import { authenticate, adminOnly } from '../middleware/auth';
 import { AuthRequest } from '../types';
 import { writeAudit, getClientIp, logInfo } from '../services/auditLog';
 import * as svc from '../services/adminService';
+import { getAdminUserDefaults, setAdminUserDefaults } from '../services/settingsService';
 import { invalidateMcpSessions } from '../mcp';
 import { getPreferencesMatrix, setAdminPreferences } from '../services/notificationPreferencesService';
 
@@ -346,6 +347,31 @@ router.post('/rotate-jwt-secret', (req: Request, res: Response) => {
   res.json({ success: true });
 });
 
+// ── Default User Settings ──────────────────────────────────────────────────────
+
+router.get('/default-user-settings', (_req: Request, res: Response) => {
+  res.json(getAdminUserDefaults());
+});
+
+router.put('/default-user-settings', (req: Request, res: Response) => {
+  if (!req.body || typeof req.body !== 'object' || Array.isArray(req.body)) {
+    return res.status(400).json({ error: 'Object body required' });
+  }
+  try {
+    setAdminUserDefaults(req.body);
+    const authReq = req as AuthRequest;
+    writeAudit({
+      userId: authReq.user.id,
+      action: 'admin.default_user_settings_update',
+      ip: getClientIp(req),
+      details: req.body,
+    });
+    res.json(getAdminUserDefaults());
+  } catch (err: any) {
+    res.status(400).json({ error: err.message });
+  }
+});
+
 // ── Dev-only: test notification endpoints ──────────────────────────────────────
 if (process.env.NODE_ENV === 'development') {
   const { send } = require('../services/notificationService');

server/src/services/settingsService.ts

@@ -3,21 +3,99 @@ import { maybe_encrypt_api_key } from './apiKeyCrypto';
 
 const ENCRYPTED_SETTING_KEYS = new Set(['webhook_url', 'ntfy_token']);
 
+export const DEFAULTABLE_USER_SETTING_KEYS = [
+  'temperature_unit',
+  'dark_mode',
+  'time_format',
+  'route_calculation',
+  'blur_booking_codes',
+  'map_tile_url',
+] as const;
+
+type DefaultableKey = typeof DEFAULTABLE_USER_SETTING_KEYS[number];
+
+const VALID_VALUES: Partial<Record<DefaultableKey, unknown[]>> = {
+  temperature_unit: ['fahrenheit', 'celsius'],
+  time_format: ['12h', '24h'],
+  dark_mode: [true, false, 'light', 'dark', 'auto'],
+};
+
+const BOOLEAN_KEYS = new Set<DefaultableKey>(['route_calculation', 'blur_booking_codes']);
+
+function parseValue(raw: string): unknown {
+  try { return JSON.parse(raw); } catch { return raw; }
+}
+
+export function getAdminUserDefaults(): Record<string, unknown> {
+  const rows = db.prepare(
+    "SELECT key, value FROM app_settings WHERE key LIKE 'default_user_setting_%'"
+  ).all() as { key: string; value: string }[];
+  const defaults: Record<string, unknown> = {};
+  for (const row of rows) {
+    const settingKey = row.key.slice('default_user_setting_'.length);
+    defaults[settingKey] = parseValue(row.value);
+  }
+  return defaults;
+}
+
+export function setAdminUserDefaults(partial: Record<string, unknown>): void {
+  const upsert = db.prepare(
+    `INSERT INTO app_settings (key, value) VALUES (?, ?)
+     ON CONFLICT(key) DO UPDATE SET value = excluded.value`
+  );
+  const del = db.prepare("DELETE FROM app_settings WHERE key = ?");
+
+  db.exec('BEGIN');
+  try {
+    for (const [key, value] of Object.entries(partial)) {
+      if (!(DEFAULTABLE_USER_SETTING_KEYS as readonly string[]).includes(key)) {
+        throw new Error(`Invalid setting key: ${key}`);
+      }
+      const typedKey = key as DefaultableKey;
+      const appKey = `default_user_setting_${key}`;
+
+      // null/undefined means "reset to built-in default" — delete the row
+      if (value === null || value === undefined) {
+        del.run(appKey);
+        continue;
+      }
+
+      if (BOOLEAN_KEYS.has(typedKey) && typeof value !== 'boolean') {
+        throw new Error(`Setting ${key} must be a boolean`);
+      }
+      const allowed = VALID_VALUES[typedKey];
+      if (allowed && !allowed.includes(value)) {
+        throw new Error(`Invalid value for ${key}: ${value}`);
+      }
+
+      upsert.run(appKey, JSON.stringify(value));
+    }
+    db.exec('COMMIT');
+  } catch (err) {
+    db.exec('ROLLBACK');
+    throw err;
+  }
+}
+
 export function getUserSettings(userId: number): Record<string, unknown> {
+  const adminDefaults = getAdminUserDefaults();
+
   const rows = db.prepare('SELECT key, value FROM settings WHERE user_id = ?').all(userId) as { key: string; value: string }[];
-  const settings: Record<string, unknown> = {};
+  const userSettings: Record<string, unknown> = {};
   for (const row of rows) {
     if (ENCRYPTED_SETTING_KEYS.has(row.key)) {
-      settings[row.key] = row.value ? '••••••••' : '';
+      userSettings[row.key] = row.value ? '••••••••' : '';
       continue;
     }
     try {
-      settings[row.key] = JSON.parse(row.value);
+      userSettings[row.key] = JSON.parse(row.value);
     } catch {
-      settings[row.key] = row.value;
+      userSettings[row.key] = row.value;
     }
   }
-  return settings;
+
+  // Admin defaults fill in only for keys the user hasn't explicitly set
+  return { ...adminDefaults, ...userSettings };
 }
 
 function serializeValue(key: string, value: unknown): string {