bugfixes, better background operation robustness and platform-specific error handling

lib/main.dart

@@ -121,10 +121,19 @@ Future<void> main() async {
     ),
   );
 
+  // Diagnostic log only. getToken() can fail transiently during cold start
+  // (Android: "IOException: FCM Registration failed!" from Play Services,
+  // iOS: apns-token-not-set until APNS registration completes), so tolerate
+  // the failure instead of letting it surface as an uncaught async error that
+  // gets reported to the telemetry backend as noise.
   unawaited(
-    FirebaseMessaging.instance.getToken().then(
-      (token) => log('Firebase token: ${token ?? "Error: no Firebase token!"}'),
-    ),
+    FirebaseMessaging.instance
+        .getToken()
+        .then(
+          (token) =>
+              log('Firebase token: ${token ?? "Error: no Firebase token!"}'),
+        )
+        .onError((e, _) => log('Firebase token unavailable: $e')),
   );
 
   // Warm up the Nextcloud root listing in the background while the user is