Refactor sound and extraction services to include user and timestamp fields

- Updated ExtractionInfo to include user_id, created_at, and updated_at fields.
- Modified ExtractionService to return user and timestamp information in extraction responses.
- Enhanced sound serialization in PlayerState to include extraction URL if available.
- Adjusted PlaylistRepository to load sound extractions when retrieving playlist sounds.
- Added tests for new fields in extraction and sound endpoints, ensuring proper response structure.
- Created new test file endpoints for sound downloads and thumbnail retrievals, including success and error cases.
- Refactored various test cases for consistency and clarity, ensuring proper mocking and assertions.

app/api/v1/sounds.py

@@ -17,7 +17,6 @@ from app.services.vlc_player import VLCPlayerService, get_vlc_player_service
 router = APIRouter(prefix="/sounds", tags=["sounds"])
 
 
-
 def get_vlc_player() -> VLCPlayerService:
     """Get the VLC player service."""
     return get_vlc_player_service(get_session_factory())
@@ -56,7 +55,6 @@ async def get_sounds(
         return {"sounds": sounds}
 
 
-
 # VLC PLAYER
 @router.post("/play/{sound_id}")
 async def play_sound_with_vlc(