feat: dark mode complet + préférences utilisateur

- Ajout du store userPreferencesStore (thème, vue, tri, pagination, lecteur)
- Page UserPreferencesPage pour configurer toutes les préférences
- Câblage des prefs dans HomePage (viewMode, sortBy, itemsPerPage), readerStore (fallback prefs), ChapterReader (autoHide, autoFullscreen, sync), useNotifications (toastDuration)
- Thème sombre (dark: Tailwind) sur tous les composants Vue : Layout, Pagination, NotificationToast, MangaCard, MangaVolume, MangaDetails, AddManga, HomePage, ActivityPage, JobItem, MangaDeleteModal, MangaEditModal, MangaPreferredSourcesModal, ManageChaptersModal, MangaChapterList, MangaChapter, ConversionPage, FileUploadArea, ConversionProgress, NewImportPage, FileImportCard, MangaMatchCard, StatusBadge, ImportResults
- i18n partiellement initialisé

Jeremy Guillot

assets/vue/app/router/index.js

@@ -8,6 +8,7 @@ import MangaDetails from '../domain/manga/presentation/pages/MangaDetails.vue';
 import ChapterPage from '../domain/reader/presentation/pages/ChapterPage.vue';
 import ScrapperConfigurations from '../domain/setting/presentation/pages/ScrapperConfigurations.vue';
 import ScrapperEdit from '../domain/setting/presentation/pages/ScrapperEdit.vue';
+import UserPreferencesPage from '../domain/setting/presentation/pages/UserPreferencesPage.vue';
 import Layout from '../shared/components/layout/Layout.vue';
 
 // Placeholder component for new routes
@@ -129,8 +130,7 @@ const routes = [
             {
                 path: '/settings/ui',
                 name: 'settings-ui',
-                component: PlaceholderComponent,
-                props: { title: "Paramètres de l'interface" }
+                component: UserPreferencesPage
             },
             // Système
             {