feat: Implement routines feature with CRUD operations and child assignment

- Add backend routines management with add, get, update, delete, and list functionalities.
- Create models for Routine, RoutineItem, RoutineSchedule, and RoutineExtension.
- Develop event types for routine confirmation and modification.
- Implement frontend components for routine assignment, confirmation dialog, and routine management views.
- Add unit tests for routine API and integration tests for routine CRUD flow.
- Create end-to-end test plan for routines feature covering parent and child interactions.

backend/models/pending_confirmation.py

@@ -3,7 +3,7 @@ from typing import Literal, Optional
 from models.base import BaseModel
 
 
-PendingEntityType = Literal['chore', 'reward']
+PendingEntityType = Literal['chore', 'reward', 'routine']
 PendingStatus = Literal['pending', 'approved', 'rejected']