Use bridge session client for desktop gateway runtime

lib/app/app_controller_desktop_core.dart

@@ -26,6 +26,7 @@ import '../runtime/gateway_acp_client.dart';
 import '../runtime/codex_runtime.dart';
 import '../runtime/codex_config_bridge.dart';
 import '../runtime/code_agent_node_orchestrator.dart';
+import '../runtime/go_gateway_runtime_desktop_client.dart';
 import '../runtime/assistant_artifacts.dart';
 import '../runtime/desktop_thread_artifact_service.dart';
 import '../runtime/external_code_agent_acp_desktop_transport.dart';
@@ -142,6 +143,7 @@ class AppController extends ChangeNotifier {
           gateway: GatewayRuntime(
             store: storeInternal,
             identityStore: DeviceIdentityStore(storeInternal),
+            sessionClient: GoGatewayRuntimeDesktopClient(),
             allowDirectSocketFallbackOnSessionClientFailure:
                 shouldBlockEmbeddedAgentLaunch(
                   isAppleHost: Platform.isIOS || Platform.isMacOS,

lib/runtime/gateway_runtime_core.dart

@@ -100,6 +100,9 @@ class GatewayRuntime extends ChangeNotifier with GatewayRuntimeHelpersInternal {
     appendLogInternal(this, level, category, message);
   }
 
+  @visibleForTesting
+  bool get usesSessionClient => sessionClientInternal != null;
+
   Future<void> initialize() async {
     sessionUpdatesInternal ??= sessionClientInternal?.updates.listen(
       _handleSessionUpdateInternal,

lib/runtime/go_acp_stdio_bridge.dart

@@ -46,6 +46,8 @@ class GoAcpStdioBridge {
   Stream<Map<String, dynamic>> get notifications =>
       _notificationsController.stream;
 
+  bool get isStarted => _process != null || _startupFuture != null;
+
   Future<Map<String, dynamic>> request({
     required String method,
     required Map<String, dynamic> params,

lib/runtime/go_gateway_runtime_desktop_client.dart

@@ -67,6 +67,9 @@ class GoGatewayRuntimeDesktopClient implements GatewayRuntimeSessionClient {
 
   @override
   Future<void> disconnect({required String runtimeId}) async {
+    if (!_bridge.isStarted) {
+      return;
+    }
     await _request(
       method: 'xworkmate.gateway.disconnect',
       params: <String, dynamic>{'runtimeId': runtimeId},

test/app_controller_desktop_gateway_bridge_client_test.dart

@@ -0,0 +1,13 @@
+import 'package:flutter_test/flutter_test.dart';
+import 'package:xworkmate/app/app_controller_desktop_core.dart';
+
+void main() {
+  TestWidgetsFlutterBinding.ensureInitialized();
+
+  test('default desktop controller wires gateway runtime through bridge client', () {
+    final controller = AppController();
+    addTearDown(controller.dispose);
+
+    expect(controller.runtime.usesSessionClient, isTrue);
+  });
+}