added telemetry call on app resume with 15 minute cooldown

lib/app.dart

@@ -46,9 +46,11 @@ class _AppState extends State<App> with WidgetsBindingObserver {
   int _knownTotalTabs = 1;
   int _lastTabIndex = 0;
   bool _userOnLastTab = false;
+  DateTime? _lastTelemetryAt;
 
   static const Duration _chatListActiveInterval = Duration(seconds: 15);
   static const Duration _chatListIdleInterval = Duration(seconds: 60);
+  static const Duration _telemetryInterval = Duration(minutes: 15);
 
   void _onTabControllerChanged() {
     final newIndex = Main.bottomNavigator.index;
@@ -73,10 +75,29 @@ class _AppState extends State<App> with WidgetsBindingObserver {
     if (talkIsActive) bloc.refresh();
   }
 
+  // Wall-clock throttle rather than Debouncer.throttle: a Timer does not tick
+  // reliably while the app is suspended, so the window would still be open on
+  // the resume it is supposed to let through.
+  void _reportTelemetry() {
+    if (!mounted) return;
+    final now = DateTime.now();
+    final last = _lastTelemetryAt;
+    if (last != null && now.difference(last) < _telemetryInterval) return;
+    _lastTelemetryAt = now;
+    TelemetryHeartbeat.report(
+      notificationsEnabled: context
+          .read<SettingsCubit>()
+          .val()
+          .notificationSettings
+          .enabled,
+    );
+  }
+
   @override
   void didChangeAppLifecycleState(AppLifecycleState state) {
     log('AppLifecycle: $state');
     if (state == AppLifecycleState.resumed) {
+      _reportTelemetry();
       Debouncer.throttle('appLifecycleState', const Duration(seconds: 10), () {
         if (!mounted) return;
         log('Refreshing due to LifecycleChange');
@@ -178,10 +199,7 @@ class _AppState extends State<App> with WidgetsBindingObserver {
       if (mounted) setState(() {});
     });
 
-    TelemetryHeartbeat.report(
-      notificationsEnabled:
-          context.read<SettingsCubit>().val().notificationSettings.enabled,
-    );
+    _reportTelemetry();
 
     // A refreshed FCM token invalidates the existing push subscription — the
     // NC device identifier stays stable, so we simply re-register (NC first,