feat: enhance unified collection with workspace commands and backdrop handling

- Added WorkspaceViewCommandService to UnifiedCollectionPageComponent for workspace layout commands.
- Implemented clear current view command for favorites and recent items.
- Updated unified favorites data service to use buildXtreamCollectionUid for UID generation.
- Enhanced unified recent data service to normalize timestamps and handle backdrop URLs.
- Introduced withRecentItems feature to manage recent item additions with backdrop support.
- Updated VodDetailsRouteComponent and SerialDetailsComponent to backfill content backdrops.
- Modified IXtreamDataSource interface to include backdrop URL handling for favorites and recent items.
- Added tests for recent items feature to ensure correct functionality and backdrop handling.

libs/shared/interfaces/src/lib/portal-activity-item.interface.ts

@@ -16,6 +16,13 @@ export interface PortalActivityItem {
     category_id: string | number;
     xtream_id: string | number;
     poster_url?: string;
+    /**
+     * Wide backdrop URL (typically 16:9), persisted when the user first views
+     * the detail page. Absent for stalker and for items that have never had
+     * their detail page opened. Dashboards should fall back to a blurred
+     * `poster_url` when undefined.
+     */
+    backdrop_url?: string;
     source?: 'xtream' | 'stalker' | 'm3u';
     /** Original stalker item for navigation state; undefined for xtream. */
     stalker_item?: StalkerPortalItem;