mobile v1.0.4：初始化步骤打点，超时可区分卡在 存储目录/建目录/SDK内核；初始化超时放宽到 30s（B-58）

mobile/lib/services/im_service.dart

@@ -130,11 +130,17 @@ class IMService extends ChangeNotifier {
     });
   }
 
+  /// 初始化进行到哪一步（超时时展示，区分卡在获取目录还是 SDK 内核）
+  String lastInitStep = '还没开始';
+
   Future<void> _doInit() async {
+    lastInitStep = '① 获取存储目录';
     final dir = await getApplicationDocumentsDirectory();
     final dataDir = '${dir.path}/openim';
     _dataDir = dataDir;
+    lastInitStep = '② 创建数据目录';
     await Directory(dataDir).create(recursive: true);
+    lastInitStep = '③ 启动消息组件内核';
     final ok = await OpenIM.iMManager.initSDK(
       platformID: platformID,
       apiAddr: apiAddr,
@@ -162,6 +168,7 @@ class IMService extends ChangeNotifier {
         onUserTokenInvalid: _forceLogout,
       ),
     );
+    lastInitStep = '④ 内核已返回（结果：$ok）';
     sdkReady = ok == true;
     _setBusinessListeners();
     notifyListeners();