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.

test_api_task.py

@@ -4,21 +4,21 @@
 import asyncio
 from datetime import datetime, timedelta
 
-from app.core.database import get_session_factory
 from app.main import get_global_scheduler_service
-from app.models.scheduled_task import TaskType, RecurrenceType
+from app.models.scheduled_task import RecurrenceType, TaskType
+
 
 async def test_api_task_creation():
     """Test creating a task through the scheduler service (simulates API call)."""
     try:
         scheduler_service = get_global_scheduler_service()
-        
+
         # Create a task for 2 minutes from now
         future_time = datetime.utcnow() + timedelta(minutes=2)
-        
+
         print(f"Creating task scheduled for: {future_time}")
         print(f"Current time: {datetime.utcnow()}")
-        
+
         task = await scheduler_service.create_task(
             name=f"API Test Task {future_time.strftime('%H:%M:%S')}",
             task_type=TaskType.PLAY_SOUND,
@@ -28,13 +28,13 @@ async def test_api_task_creation():
             timezone="UTC",
             recurrence_type=RecurrenceType.NONE,
         )
-        
+
         print(f"Created task: {task.name} (ID: {task.id})")
         print(f"Task will execute in: {future_time - datetime.utcnow()}")
         print("Task should be automatically scheduled in APScheduler!")
-        
+
     except Exception as e:
         print(f"Error: {e}")
 
 if __name__ == "__main__":
-    asyncio.run(test_api_task_creation())
+    asyncio.run(test_api_task_creation())