feat: Implement scheduling functionality for playlist synchronization

- Added a new scheduler module using APScheduler to manage scheduled sync jobs.
- Introduced cron expression validation and job scheduling based on user-defined settings.
- Enhanced frontend to support schedule settings, including cron, daily, and weekly modes.
- Updated API service to handle fetching and saving schedule settings.
- Modified StrategySelector component to include schedule management UI.
- Added new types for schedule settings and modes in the frontend.
- Updated requirements to include APScheduler for scheduling capabilities.

docker-compose.yml

@@ -5,7 +5,7 @@ services:
     ports:
       - "8888:8080"
     volumes:
-      - path_to_your_playlist:/app/playlist
+      - /D/WorkSpace/Python/PlexPlaylistSync/playlist:/app/playlist
     environment:
       - PYTHONUNBUFFERED=1
       - PYTHONDONTWRITEBYTECODE=1