fix foreground service and add notification nav

wraps MaterialApp in WithForegroundService to keep alive when swiped away

persists last connected device and clears on manual disconnect to allow
reconnect after kill

added lifecycle tracking to iOS and keep android notification alive with
heartbeat

add notification navigation

change screen tests to be less brittle

address PR commnets

lib/screens/discovery_screen.dart

@@ -8,6 +8,7 @@ import '../connector/meshcore_connector.dart';
 import '../connector/meshcore_protocol.dart';
 import '../l10n/l10n.dart';
 import '../models/contact.dart';
+import '../services/notification_service.dart';
 import '../utils/contact_search.dart';
 import '../utils/platform_info.dart';
 import '../widgets/app_bar.dart';
@@ -31,6 +32,20 @@ class _DiscoveryScreenState extends State<DiscoveryScreen> {
   DiscoverySortOption discoverySortOption = DiscoverySortOption.lastSeen;
   Timer? _searchDebounce;
 
+  @override
+  void initState() {
+    super.initState();
+    _clearAdvertNotifications();
+  }
+
+  void _clearAdvertNotifications() {
+    final connector = context.read<MeshCoreConnector>();
+    final ids = connector.allContacts.map((c) => c.publicKeyHex).toList();
+    final ns = NotificationService();
+    ns.clearAllAdvertNotifications();
+    ns.clearAdvertNotifications(ids);
+  }
+
   @override
   void dispose() {
     _searchController.dispose();