feat(04-02): add widget tests for notification settings UI

- 5 tests for Benachrichtigungen section: header rendering, toggle OFF default,
  time picker visibility on/off with AnimatedSize, formatted time display
- Uses notificationSettingsProvider.overrideWithValue for test isolation
- Uses themeProvider.overrideWithValue to avoid SharedPreferences dependency
- UncontrolledProviderScope + ProviderContainer follows home_screen_test pattern
- All 89 tests pass (84 existing + 5 new)

test/features/settings/settings_screen_test.dart

@@ -0,0 +1,109 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:shared_preferences/shared_preferences.dart';
+
+import 'package:household_keeper/core/notifications/notification_settings_notifier.dart';
+import 'package:household_keeper/core/theme/theme_provider.dart';
+import 'package:household_keeper/features/settings/presentation/settings_screen.dart';
+import 'package:household_keeper/l10n/app_localizations.dart';
+
+/// Build a standalone SettingsScreen with provider overrides for test isolation.
+Widget _buildSettings(NotificationSettings notifSettings) {
+  final container = ProviderContainer(overrides: [
+    notificationSettingsProvider.overrideWithValue(notifSettings),
+    themeProvider.overrideWithValue(ThemeMode.system),
+  ]);
+
+  return UncontrolledProviderScope(
+    container: container,
+    child: const MaterialApp(
+      localizationsDelegates: AppLocalizations.localizationsDelegates,
+      supportedLocales: [Locale('de')],
+      locale: Locale('de'),
+      home: Scaffold(body: SettingsScreen()),
+    ),
+  );
+}
+
+void main() {
+  setUp(() {
+    SharedPreferences.setMockInitialValues({});
+  });
+
+  group('SettingsScreen Benachrichtigungen section', () {
+    testWidgets('renders Benachrichtigungen section header', (tester) async {
+      await tester.pumpWidget(_buildSettings(const NotificationSettings(
+        enabled: false,
+        time: TimeOfDay(hour: 7, minute: 0),
+      )));
+      await tester.pumpAndSettle();
+
+      expect(find.text('Benachrichtigungen'), findsOneWidget);
+    });
+
+    testWidgets(
+      'notification toggle displays with correct label and defaults to OFF',
+      (tester) async {
+        await tester.pumpWidget(_buildSettings(const NotificationSettings(
+          enabled: false,
+          time: TimeOfDay(hour: 7, minute: 0),
+        )));
+        await tester.pumpAndSettle();
+
+        // Label matches ARB notificationsEnabledLabel
+        expect(find.text('Tägliche Erinnerung'), findsOneWidget);
+
+        // SwitchListTile with value=false
+        final switchTile = tester.widget<SwitchListTile>(
+          find.byType(SwitchListTile),
+        );
+        expect(switchTile.value, isFalse);
+      },
+    );
+
+    testWidgets(
+      'time picker row is visible when notifications are enabled',
+      (tester) async {
+        await tester.pumpWidget(_buildSettings(const NotificationSettings(
+          enabled: true,
+          time: TimeOfDay(hour: 9, minute: 30),
+        )));
+        await tester.pumpAndSettle();
+
+        // notificationsTimeLabel should be visible
+        expect(find.text('Uhrzeit'), findsOneWidget);
+        // Formatted time should be shown (09:30)
+        expect(find.text('09:30'), findsOneWidget);
+      },
+    );
+
+    testWidgets(
+      'time picker row is hidden when notifications are disabled',
+      (tester) async {
+        await tester.pumpWidget(_buildSettings(const NotificationSettings(
+          enabled: false,
+          time: TimeOfDay(hour: 9, minute: 30),
+        )));
+        await tester.pumpAndSettle();
+
+        // notificationsTimeLabel should NOT be visible
+        expect(find.text('Uhrzeit'), findsNothing);
+      },
+    );
+
+    testWidgets(
+      'time picker row displays correctly formatted time when enabled',
+      (tester) async {
+        await tester.pumpWidget(_buildSettings(const NotificationSettings(
+          enabled: true,
+          time: TimeOfDay(hour: 7, minute: 0),
+        )));
+        await tester.pumpAndSettle();
+
+        // Default time 07:00 should display as formatted string
+        expect(find.text('07:00'), findsOneWidget);
+      },
+    );
+  });
+}