TF-4268 Refactor app runner: split web/mobile runners, add platform error handlers

lib/main/runner/app_runner_base.dart

@@ -0,0 +1,12 @@
+import 'dart:async';
+
+import 'package:sentry_flutter/sentry_flutter.dart';
+import 'package:tmail_ui_user/main/runner/app_error_handlers.dart';
+
+Future<void> runAppGuarded(Future<void> Function() runner) async {
+  SentryWidgetsFlutterBinding.ensureInitialized();
+
+  setupErrorHooks();
+
+  await runner();
+}