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/tests/test_user_api.py

@@ -227,3 +227,36 @@ def test_update_profile_success(authenticated_client):
     assert user['first_name'] == 'Updated'
     assert user['last_name'] == 'Name'
     assert user['image_id'] == 'new_image'
+
+
+def test_get_profile_includes_email_digest_enabled(authenticated_client):
+    """GET /user/profile response includes email_digest_enabled field."""
+    response = authenticated_client.get('/user/profile')
+    assert response.status_code == 200
+    data = response.get_json()
+    assert 'email_digest_enabled' in data
+    assert isinstance(data['email_digest_enabled'], bool)
+
+
+def test_update_profile_disables_digest(authenticated_client):
+    """PUT /user/profile with email_digest_enabled: false disables the digest."""
+    # Ensure it starts enabled
+    users_db.update({'email_digest_enabled': True}, Query().email == TEST_EMAIL)
+
+    response = authenticated_client.put('/user/profile', json={'email_digest_enabled': False})
+    assert response.status_code == 200
+
+    user = users_db.search(Query().email == TEST_EMAIL)[0]
+    assert user['email_digest_enabled'] is False
+
+
+def test_update_profile_enables_digest(authenticated_client):
+    """PUT /user/profile with email_digest_enabled: true re-enables the digest."""
+    # Start disabled
+    users_db.update({'email_digest_enabled': False}, Query().email == TEST_EMAIL)
+
+    response = authenticated_client.put('/user/profile', json={'email_digest_enabled': True})
+    assert response.status_code == 200
+
+    user = users_db.search(Query().email == TEST_EMAIL)[0]
+    assert user['email_digest_enabled'] is True