feat(channel): page details chaine multi-providers avec onglets et infinite scroll

- Strategy Pattern front: ChannelProviderInterface + 6 providers (yt/dm/tw/pt/od/ru) + factory (ids longs/courts)
- ChannelContentService: cache par onglet/tri/recherche (TTL 5min), pagination nextPage
- ChannelPage: header (banniere/avatar/subs/description ...plus), tabs dynamiques par capabilities, grilles videos/shorts 9:16/playlists/live, recherche debounced, tri recent/populaire, infinite scroll IntersectionObserver, skeletons/empty/error
- Backend: GET /api/channels/:provider/:id/content (videos/shorts/playlists/live) natif par provider

src/app.routes.ts

@@ -23,6 +23,11 @@ export const APP_ROUTES: Routes = [
     loadComponent: () => import('./components/shorts/watch-short.component').then(m => m.WatchShortComponent),
     title: 'NewTube - Shorts'
   },
+  {
+    path: 'channel/:provider/:externalId',
+    loadComponent: () => import('./components/channel/channel-page.component').then(m => m.ChannelPageComponent),
+    title: 'NewTube - Channel'
+  },
   {
     path: 'watch/:id',
     loadComponent: () => import('./components/watch/watch.component').then(m => m.WatchComponent),
@@ -59,6 +64,16 @@ export const APP_ROUTES: Routes = [
     loadComponent: () => import('./components/library/subscriptions/subscriptions.component').then(m => m.SubscriptionsComponent),
     title: 'NewTube - Subscriptions'
   },
+  {
+    path: 'library/downloads/:id',
+    loadComponent: () => import('./components/library/downloads/download-play.component').then(m => m.DownloadPlayComponent),
+    title: 'NewTube - Play download'
+  },
+  {
+    path: 'library/downloads',
+    loadComponent: () => import('./components/library/downloads/downloads.component').then(m => m.DownloadsComponent),
+    title: 'NewTube - Downloads'
+  },
   {
     path: 'account',
     pathMatch: 'full',