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/repositories/playlist.py

@@ -1,6 +1,7 @@
 """Playlist repository for database operations."""
 
 from sqlalchemy import func
+from sqlalchemy.orm import selectinload
 from sqlmodel import select
 from sqlmodel.ext.asyncio.session import AsyncSession
 
@@ -84,11 +85,12 @@ class PlaylistRepository(BaseRepository[Playlist]):
             raise
 
     async def get_playlist_sounds(self, playlist_id: int) -> list[Sound]:
-        """Get all sounds in a playlist, ordered by position."""
+        """Get all sounds in a playlist with extractions, ordered by position."""
         try:
             statement = (
                 select(Sound)
                 .join(PlaylistSound)
+                .options(selectinload(Sound.extractions))
                 .where(PlaylistSound.playlist_id == playlist_id)
                 .order_by(PlaylistSound.position)
             )