feat: Implement favorites management API; add endpoints for adding, removing, and retrieving favorites for sounds and playlists

feat: Create Favorite model and repository for managing user favorites in the database
feat: Add FavoriteService to handle business logic for favorites management
feat: Enhance Playlist and Sound response schemas to include favorite indicators and counts
refactor: Update API routes to include favorites functionality in playlists and sounds

app/api/v1/__init__.py

@@ -7,6 +7,7 @@ from app.api.v1 import (
     auth,
     dashboard,
     extractions,
+    favorites,
     files,
     main,
     player,
@@ -22,6 +23,7 @@ api_router = APIRouter(prefix="/v1")
 api_router.include_router(auth.router, tags=["authentication"])
 api_router.include_router(dashboard.router, tags=["dashboard"])
 api_router.include_router(extractions.router, tags=["extractions"])
+api_router.include_router(favorites.router, tags=["favorites"])
 api_router.include_router(files.router, tags=["files"])
 api_router.include_router(main.router, tags=["main"])
 api_router.include_router(player.router, tags=["player"])