fix(ui): never hang on a blank frame when the hub is unreachable

main() awaited the hub health probe before runApp(); a gRPC-web
error out of HubRepository.connect propagated and left the app on a
white page. Guard the settings+probe in main() with a MockRepository
fallback so the first frame always paints.

Signed-off-by: flemming-it <sf@flemming.it>

app/lib/main.dart

@@ -9,8 +9,22 @@ import 'theme/reclaim_theme.dart';
 
 void main() async {
   WidgetsFlutterBinding.ensureInitialized();
-  final settings = await HubSettings.load();
+  // Acquiring settings + probing the hub must never prevent the
-  final repository = await _pickRepository(settings);
+  // first frame. Any failure here falls back to demo data so the
+  // app always paints instead of hanging on a blank page.
+  HubSettings settings;
+  EvaluationRepository repository;
+  try {
+    settings = await HubSettings.load();
+    repository = await _pickRepository(settings);
+  } catch (_) {
+    settings = const HubSettings(
+      host: HubSettings.defaultHost,
+      port: HubSettings.defaultPort,
+      secure: false,
+    );
+    repository = const MockRepository();
+  }
   runApp(ReclaimApp(repository: repository, settings: settings));
 }