feat: add external playback support and UI enhancements

- Integrated external playback functionality in category and detail views.
- Updated styles for play buttons to reflect different states (idle, launching, stop).
- Enhanced episode cards to indicate launching and active external playback states.
- Added new computed properties for managing external playback session states.
- Improved user interface for playback buttons with dynamic labels and icons based on playback state.
- Introduced new settings option to show external playback status bar on desktop.
- Updated translations for new features and UI elements.

libs/shared/interfaces/src/lib/settings.interface.ts

@@ -22,6 +22,8 @@ export interface Settings {
     streamFormat: StreamFormat;
     language: Language;
     showCaptions: boolean;
+    /** Show the desktop footer bar for external playback status */
+    showExternalPlaybackBar?: boolean;
     theme: Theme;
     mpvPlayerPath: string;
     mpvReuseInstance: boolean;