feat: 修复节点切换bug

lib/app/modules/kr_home/controllers/kr_home_controller.dart

@@ -1504,6 +1504,7 @@ class KRHomeController extends GetxController with WidgetsBindingObserver {
           },
           (_) {
             // 切换成功
+            KRSingBoxImp.instance.kr_startNodeSelectionMonitor(tag);
             KRLogUtil.kr_i('✅ selectOutbound 调用成功', tag: 'HomeController');
           },
         );

lib/app/services/singbox_imp/kr_sing_box_imp.dart

@@ -1635,9 +1635,7 @@ class KRSingBoxImp {
       KRLogUtil.kr_i('🛑 停止 SingBox 服务...', tag: 'SingBox');
 
       // 取消节点选择监控定时器
-      _nodeSelectionTimer?.cancel();
-      _nodeSelectionTimer = null;
-      KRLogUtil.kr_i('✅ 节点选择监控已停止', tag: 'SingBox');
+      kr_resetNodeSelectionMonitor();
 
       await Future.delayed(const Duration(milliseconds: 100));
 
@@ -1977,7 +1975,22 @@ class KRSingBoxImp {
 
     // 🔄 如果用户选择了具体节点（不是 auto），启动定期检查和重新选择
     // 这是为了防止 urltest 自动覆盖用户的手动选择
-    _nodeSelectionTimer?.cancel();
+    kr_startNodeSelectionMonitor(tag);
+  }
+
+  /// 配合文件地址
+
+  Directory get directory =>
+      Directory(p.join(kr_configDics.workingDir.path, "configs"));
+  File _file(String fileName) {
+    return File(p.join(directory.path, "$fileName.json"));
+  }
+
+  File _tempFile(String fileName) => _file("$fileName.tmp");
+
+  /// 启动节点选择监控定时器，防止用户手动选择被自动策略覆盖
+  void kr_startNodeSelectionMonitor(String tag) {
+    kr_resetNodeSelectionMonitor();
     if (tag != 'auto') {
       KRLogUtil.kr_i('🔁 启动节点选择监控，防止被 auto 覆盖', tag: 'SingBox');
       _nodeSelectionTimer =
@@ -1997,16 +2010,13 @@ class KRSingBoxImp {
     }
   }
 
-  /// 配合文件地址
-
-  Directory get directory =>
-      Directory(p.join(kr_configDics.workingDir.path, "configs"));
-  File _file(String fileName) {
-    return File(p.join(directory.path, "$fileName.json"));
+  /// 重置并停止节点选择监控定时器
+  void kr_resetNodeSelectionMonitor() {
+    _nodeSelectionTimer?.cancel();
+    _nodeSelectionTimer = null;
+    KRLogUtil.kr_i('✅ 节点选择监控已停止', tag: 'SingBox');
   }
 
-  File _tempFile(String fileName) => _file("$fileName.tmp");
-
   // File tempFile(String fileName) => file("$fileName.tmp");
 
   Future<void> kr_urlTest(String groupTag) async {