Gate push toggle on backend notification method

Add a GET /api/config endpoint exposing the front-end-facing backend
configuration (currently the notification delivery method, grouped under
a nested "notifications" object so the shape can grow). The settings
screen fetches it on init and only shows the per-device push toggle when
the backend method is "push" (and the platform supports push, which keeps
it off the browser).

Also fold in related push-notifications cleanups: fix the Android app
label ("frontend" -> "OOTT") so the notification permission dialog reads
correctly, remove the completed push_notifications.md plan, and update
TODO.md.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

frontend/test/api/config_api_test.dart

@@ -0,0 +1,26 @@
+import 'package:flutter_test/flutter_test.dart';
+import 'package:frontend/utils/oott_api.dart';
+import 'package:http_mock_adapter/http_mock_adapter.dart';
+
+import '../helpers/backend_test_harness.dart';
+
+void main() {
+  late DioAdapter adapter;
+
+  setUp(() async {
+    adapter = await setUpBackendForTest();
+  });
+
+  test('getConfig GETs /config and decodes the notification method', () async {
+    adapter.onGet(
+      '/config',
+      (server) => server.reply(200, {
+        'notifications': {'method': 'push'},
+      }),
+    );
+
+    final config = await BackendAPI.instance.getConfig();
+
+    expect(config.notificationMethod, 'push');
+  });
+}

frontend/test/widget/settings_push_test.dart

@@ -4,6 +4,7 @@ import 'package:flutter_test/flutter_test.dart';
 import 'package:frontend/settings/settings.dart';
 import 'package:frontend/utils/pref_utils.dart';
 import 'package:frontend/utils/push_service.dart';
+import 'package:http_mock_adapter/http_mock_adapter.dart';
 
 import '../helpers/backend_test_harness.dart';
 import '../helpers/pump_app.dart';
@@ -35,8 +36,10 @@ class _FakePushService implements PushService {
 const _toggleText = 'Push notifications on this device';
 
 void main() {
+  late DioAdapter adapter;
+
   setUp(() async {
-    await setUpBackendForTest(
+    adapter = await setUpBackendForTest(
       prefs: {
         'base_url': 'http://my.server/api',
         'api_key': XOR().xorEncode('topsecret'),
@@ -48,24 +51,59 @@ void main() {
     await PrefUtil.setValue('push_enabled', false);
   });
 
-  testWidgets('shows the push toggle on a supported platform', (tester) async {
+  // Stubs the backend config endpoint the settings screen reads on load.
+  void stubNotificationMethod(String method) {
+    adapter.onGet(
+      '/config',
+      (server) => server.reply(200, {
+        'notifications': {'method': method},
+      }),
+    );
+  }
+
+  // Pumps frames so the async config load (resolved via Dio's zero-duration
+  // timer) settles, for assertions that expect the toggle to be absent.
+  Future<void> settleConfig(WidgetTester tester) async {
+    for (var i = 0; i < 10; i++) {
+      await tester.pump(const Duration(milliseconds: 10));
+    }
+  }
+
+  testWidgets('shows the push toggle when the backend method is push', (
+    tester,
+  ) async {
+    stubNotificationMethod('push');
     await pumpScreen(tester, Settings(pushService: _FakePushService()));
+    await pumpUntilFound(tester, find.text(_toggleText));
     expect(find.text(_toggleText), findsOneWidget);
   });
 
   testWidgets('hides the push toggle when push is unsupported', (tester) async {
+    stubNotificationMethod('push');
     await pumpScreen(
       tester,
       Settings(pushService: _FakePushService(supported: false)),
     );
+    await settleConfig(tester);
+    expect(find.text(_toggleText), findsNothing);
+  });
+
+  testWidgets('hides the push toggle when the backend method is not push', (
+    tester,
+  ) async {
+    stubNotificationMethod('pushover');
+    await pumpScreen(tester, Settings(pushService: _FakePushService()));
+    await settleConfig(tester);
     expect(find.text(_toggleText), findsNothing);
   });
 
   testWidgets('enabling push registers and shows a success message', (
     tester,
   ) async {
+    stubNotificationMethod('push');
     final service = _FakePushService(enableResult: true);
     await pumpScreen(tester, Settings(pushService: service));
+    await pumpUntilFound(tester, find.byType(SwitchListTile));
 
     await tester.tap(find.byType(SwitchListTile));
     await pumpUntilFound(
@@ -75,31 +113,38 @@ void main() {
 
     expect(service.enableCalls, 1);
     expect(PrefUtil.getValue('push_enabled', false), isTrue);
-    expect(tester.widget<SwitchListTile>(find.byType(SwitchListTile)).value, isTrue);
+    expect(
+      tester.widget<SwitchListTile>(find.byType(SwitchListTile)).value,
+      isTrue,
+    );
   });
 
   testWidgets('a declined permission leaves the toggle off with an error', (
     tester,
   ) async {
+    stubNotificationMethod('push');
     final service = _FakePushService(enableResult: false);
     await pumpScreen(tester, Settings(pushService: service));
+    await pumpUntilFound(tester, find.byType(SwitchListTile));
 
     await tester.tap(find.byType(SwitchListTile));
-    await pumpUntilFound(
-      tester,
-      find.textContaining('Could not enable push'),
-    );
+    await pumpUntilFound(tester, find.textContaining('Could not enable push'));
 
     expect(service.enableCalls, 1);
-    expect(tester.widget<SwitchListTile>(find.byType(SwitchListTile)).value, isFalse);
+    expect(
+      tester.widget<SwitchListTile>(find.byType(SwitchListTile)).value,
+      isFalse,
+    );
   });
 
   testWidgets('disabling push unregisters and shows a success message', (
     tester,
   ) async {
+    stubNotificationMethod('push');
     await PrefUtil.setValue('push_enabled', true);
     final service = _FakePushService();
     await pumpScreen(tester, Settings(pushService: service));
+    await pumpUntilFound(tester, find.byType(SwitchListTile));
 
     // Starts on because the stored intent is enabled.
     expect(

frontend/test/widget/settings_test.dart

@@ -9,17 +9,27 @@ import '../helpers/pump_app.dart';
 
 void main() {
   setUp(() async {
-    await setUpBackendForTest(
+    final adapter = await setUpBackendForTest(
       prefs: {
         'base_url': 'http://my.server/api',
         'api_key': XOR().xorEncode('topsecret'),
         'theme': 'catppuccin_mocha',
       },
     );
+    // Settings loads the backend config on init; these tests don't exercise the
+    // push toggle, so report a non-push method to keep it hidden.
+    adapter.onGet(
+      '/config',
+      (server) => server.reply(200, {
+        'notifications': {'method': 'none'},
+      }),
+    );
   });
 
   testWidgets('prefills the form from stored preferences', (tester) async {
     await pumpScreen(tester, const Settings());
+    // Let the on-init config request resolve so its timer doesn't leak.
+    await tester.pump(const Duration(milliseconds: 10));
 
     expect(find.text('http://my.server/api'), findsOneWidget);
     expect(find.text('Catppuccin Mocha'), findsOneWidget);
@@ -78,6 +88,7 @@ void main() {
   ) async {
     await PrefUtil.setValue('base_url', '');
     await pumpScreen(tester, const Settings());
+    await tester.pump(const Duration(milliseconds: 10));
 
     expect(find.textContaining('Welcome to OOTT'), findsOneWidget);
   });
@@ -87,6 +98,7 @@ void main() {
   ) async {
     await PrefUtil.setValue('base_url', 'http://my.server/api');
     await pumpScreen(tester, const Settings());
+    await tester.pump(const Duration(milliseconds: 10));
 
     expect(find.textContaining('Welcome to OOTT'), findsNothing);
   });