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

.github/workflows/ci.yml

@@ -0,0 +1,44 @@
+name: CI
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+
+jobs:
+  build-and-test:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: actions/setup-node@v4
+        with:
+          node-version: 22
+          cache: npm
+
+      - name: Install dependencies
+        run: npm ci
+
+      - name: Typecheck (front + shared tsconfig)
+        run: npx tsc --noEmit
+
+      - name: Build Angular app
+        run: npm run build
+
+      - name: Server tests (playlists visibility)
+        run: npm run test:playlists
+
+      - name: Server tests (download jobs)
+        run: npm run test:downloads
+
+      - name: Server tests (preferences)
+        run: npm run test:preferences
+
+      - name: Server tests (telemetry)
+        run: npm run test:telemetry
+
+      - name: Unit tests (search UX)
+        run: npm run test:search
+
+      - name: E2E scenarios (search UX)
+        run: npm run test:search-e2e