Add comprehensive backend services and API enhancements

- Complete Spotify integration with downloader and settings
- Advanced UX features and audio quality management
- Enhanced search capabilities and mobile offline support
- Music catalog browser and recap features
- Universal downloader and upload functionality
- Update tracking system with database models and migrations
- Comprehensive service layer architecture
- Enhanced lyrics API and streaming capabilities
- Extended application builder and startup configuration
- New logging infrastructure and services directory

src/swingmusic/app_builder.py

@@ -86,6 +86,33 @@ def load_endpoints(web: OpenAPI):
         # Auth
         web.register_api(swing_api.auth.api)
 
+        # Spotify Downloader
+        web.register_api(swing_api.spotify.api)
+        web.register_api(swing_api.spotify_settings.api)
+        
+        # Enhanced Search
+        from swingmusic.api.enhanced_search import register_enhanced_search_api
+        register_enhanced_search_api(web)
+        
+        # Universal Music Downloader
+        from swingmusic.api.universal_downloader import register_universal_downloader_api
+        register_universal_downloader_api(web)
+        
+        # Update Tracking
+        web.register_blueprint(swing_api.update_tracking.update_tracking_bp)
+        
+        # Audio Quality Management
+        web.register_blueprint(swing_api.audio_quality.audio_quality_bp)
+        
+        # Music Catalog Service
+        web.register_blueprint(swing_api.music_catalog.music_catalog_bp)
+        
+        # Advanced UX Service
+        web.register_blueprint(swing_api.advanced_ux.advanced_ux_bp)
+        
+        # Mobile Offline Service
+        web.register_blueprint(swing_api.mobile_offline.mobile_offline_bp)
+
 
 def load_plugins(web: OpenAPI):
         # TODO: rework plugin support