- Moved _sync_series_to_database from fastapi_app.py to anime_service.py
- Renamed to sync_series_from_data_files for better clarity
- Updated all imports and test references
- Removed completed TODO tasks from instructions.md
- Add get_all_series_from_data_files() to SeriesApp
- Sync series from data files to DB on startup
- Add unit tests for new SeriesApp method
- Add integration tests for sync functionality
- Update documentation
