Add push notification functionality with tests and digest scheduler

- Implemented push subscription API with tests for subscribing and unsubscribing users.
- Created web push notification tests triggered by child actions.
- Added digest scheduler to send email digests to users at 9 PM local time.
- Developed utility functions for creating and validating digest action tokens.
- Integrated web push sender to handle sending notifications to users.
- Added service worker for handling push notifications in the frontend.
- Created a push opt-in component for user notification preferences.
- Implemented tests for the push opt-in component to ensure correct behavior.
- Updated frontend services to manage push subscriptions and permissions.

backend/db/db.py

@@ -79,6 +79,8 @@ child_overrides_path = os.path.join(base_dir, 'child_overrides.json')
 chore_schedules_path = os.path.join(base_dir, 'chore_schedules.json')
 task_extensions_path = os.path.join(base_dir, 'task_extensions.json')
 refresh_tokens_path = os.path.join(base_dir, 'refresh_tokens.json')
+push_subscriptions_path = os.path.join(base_dir, 'push_subscriptions.json')
+digest_action_tokens_path = os.path.join(base_dir, 'digest_action_tokens.json')
 
 # Use separate TinyDB instances/files for each collection
 _child_db = TinyDB(child_path, indent=2)
@@ -93,6 +95,8 @@ _child_overrides_db = TinyDB(child_overrides_path, indent=2)
 _chore_schedules_db = TinyDB(chore_schedules_path, indent=2)
 _task_extensions_db = TinyDB(task_extensions_path, indent=2)
 _refresh_tokens_db = TinyDB(refresh_tokens_path, indent=2)
+_push_subscriptions_db = TinyDB(push_subscriptions_path, indent=2)
+_digest_action_tokens_db = TinyDB(digest_action_tokens_path, indent=2)
 
 # Expose table objects wrapped with locking
 child_db = LockedTable(_child_db)
@@ -107,6 +111,8 @@ child_overrides_db = LockedTable(_child_overrides_db)
 chore_schedules_db = LockedTable(_chore_schedules_db)
 task_extensions_db = LockedTable(_task_extensions_db)
 refresh_tokens_db = LockedTable(_refresh_tokens_db)
+push_subscriptions_db = LockedTable(_push_subscriptions_db)
+digest_action_tokens_db = LockedTable(_digest_action_tokens_db)
 
 if os.environ.get('DB_ENV', 'prod') == 'test':
     child_db.truncate()
@@ -121,4 +127,6 @@ if os.environ.get('DB_ENV', 'prod') == 'test':
     chore_schedules_db.truncate()
     task_extensions_db.truncate()
     refresh_tokens_db.truncate()
+    push_subscriptions_db.truncate()
+    digest_action_tokens_db.truncate()