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/db/routine_schedules.py

@@ -0,0 +1,42 @@
+from tinydb import Query
+from db.db import routine_schedules_db
+from models.routine_schedule import RoutineSchedule
+
+
+def get_schedule(child_id: str, routine_id: str) -> RoutineSchedule | None:
+    q = Query()
+    result = routine_schedules_db.search((q.child_id == child_id) & (q.routine_id == routine_id))
+    if not result:
+        return None
+    return RoutineSchedule.from_dict(result[0])
+
+
+def upsert_schedule(schedule: RoutineSchedule) -> None:
+    q = Query()
+    existing = routine_schedules_db.get((q.child_id == schedule.child_id) & (q.routine_id == schedule.routine_id))
+    if existing:
+        routine_schedules_db.update(
+            schedule.to_dict(),
+            (q.child_id == schedule.child_id) & (q.routine_id == schedule.routine_id)
+        )
+    else:
+        routine_schedules_db.insert(schedule.to_dict())
+
+
+def delete_schedule(child_id: str, routine_id: str) -> bool:
+    q = Query()
+    existing = routine_schedules_db.get((q.child_id == child_id) & (q.routine_id == routine_id))
+    if not existing:
+        return False
+    routine_schedules_db.remove((q.child_id == child_id) & (q.routine_id == routine_id))
+    return True
+
+
+def delete_schedules_for_child(child_id: str) -> None:
+    q = Query()
+    routine_schedules_db.remove(q.child_id == child_id)
+
+
+def delete_schedules_for_routine(routine_id: str) -> None:
+    q = Query()
+    routine_schedules_db.remove(q.routine_id == routine_id)