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/routine_extension.py

@@ -0,0 +1,29 @@
+from dataclasses import dataclass
+from models.base import BaseModel
+
+
+@dataclass
+class RoutineExtension(BaseModel):
+    child_id: str
+    routine_id: str
+    date: str
+
+    @classmethod
+    def from_dict(cls, d: dict) -> 'RoutineExtension':
+        return cls(
+            child_id=d.get('child_id'),
+            routine_id=d.get('routine_id'),
+            date=d.get('date'),
+            id=d.get('id'),
+            created_at=d.get('created_at'),
+            updated_at=d.get('updated_at'),
+        )
+
+    def to_dict(self) -> dict:
+        base = super().to_dict()
+        base.update({
+            'child_id': self.child_id,
+            'routine_id': self.routine_id,
+            'date': self.date,
+        })
+        return base