Refactor scheduled task repository and schemas for improved type hints and consistency

- Updated type hints from List/Optional to list/None for better readability and consistency across the codebase.
- Refactored import statements for better organization and clarity.
- Enhanced the ScheduledTaskBase schema to use modern type hints.
- Cleaned up unnecessary comments and whitespace in various files.
- Improved error handling and logging in task execution handlers.
- Updated test cases to reflect changes in type hints and ensure compatibility with the new structure.

app/main.py

@@ -11,11 +11,14 @@ from app.core.database import get_session_factory, init_db
 from app.core.logging import get_logger, setup_logging
 from app.middleware.logging import LoggingMiddleware
 from app.services.extraction_processor import extraction_processor
-from app.services.player import initialize_player_service, shutdown_player_service, get_player_service
+from app.services.player import (
+    get_player_service,
+    initialize_player_service,
+    shutdown_player_service,
+)
 from app.services.scheduler import SchedulerService
 from app.services.socket import socket_manager
 
-
 scheduler_service = None
 
 
@@ -31,7 +34,7 @@ def get_global_scheduler_service() -> SchedulerService:
 async def lifespan(_app: FastAPI) -> AsyncGenerator[None]:
     """Application lifespan context manager for setup and teardown."""
     global scheduler_service
-    
+
     setup_logging()
     logger = get_logger(__name__)
     logger.info("Starting application")