fix：

wifi.py

@@ -41,6 +41,7 @@ class WiFiManager:
         # WiFi 质量监测（后台线程）
         self._wifi_quality_monitor_thread = None
         self._wifi_quality_stop_event = threading.Event()
+        self._wifi_quality_lock = threading.Lock()
         self._last_wifi_rtt_ms = None  # 最近一次测量的 RTT
         self._last_wifi_rssi_dbm = None  # 最近一次测量的 RSSI
         
@@ -542,34 +543,45 @@ class WiFiManager:
             network_type_callback: 获取当前网络类型的回调函数
             on_poor_quality_callback: WiFi质量差时的回调函数
         """
-        if self._wifi_quality_monitor_thread is not None:
-            self.logger.warning("[WiFi Monitor] 监测线程已在运行")
-            return
-        
-        self._network_type_callback = network_type_callback
-        self._on_poor_quality_callback = on_poor_quality_callback
-        self._wifi_quality_stop_event.clear()
-        self._wifi_quality_monitor_thread = threading.Thread(
-            target=self._quality_monitor_loop,
-            daemon=True,
-            name="wifi_quality_monitor"
-        )
-        self._wifi_quality_monitor_thread.start()
-        self.logger.info("[WiFi Monitor] 已启动后台监测线程")
+        with self._wifi_quality_lock:
+            if self._wifi_quality_monitor_thread is not None and self._wifi_quality_monitor_thread.is_alive():
+                self.logger.warning("[WiFi Monitor] 监测线程已在运行")
+                return
+            
+            self._network_type_callback = network_type_callback
+            self._on_poor_quality_callback = on_poor_quality_callback
+            self._wifi_quality_stop_event.clear()
+            self._wifi_quality_monitor_thread = threading.Thread(
+                target=self._quality_monitor_loop,
+                daemon=True,
+                name="wifi_quality_monitor"
+            )
+            self._wifi_quality_monitor_thread.start()
+            self.logger.info("[WiFi Monitor] 已启动后台监测线程")
     
     def stop_quality_monitor(self):
         """停止 WiFi 质量监测线程"""
-        if self._wifi_quality_monitor_thread is None:
-            return
+        with self._wifi_quality_lock:
+            t = self._wifi_quality_monitor_thread
+            if t is None:
+                return
+            if not t.is_alive():
+                self._wifi_quality_monitor_thread = None
+                return
         
         self._wifi_quality_stop_event.set()
         try:
-            self._wifi_quality_monitor_thread.join(timeout=2.0)
+            t.join(timeout=2.0)
         except Exception as e:
             self.logger.error(f"[WiFi Monitor] 停止线程失败：{e}")
-        finally:
-            self._wifi_quality_monitor_thread = None
-            self.logger.info("[WiFi Monitor] 已停止后台监测线程")
+        
+        with self._wifi_quality_lock:
+            if t is self._wifi_quality_monitor_thread:
+                if t.is_alive():
+                    self.logger.warning("[WiFi Monitor] 线程未在超时内退出，保留引用防止重复创建")
+                else:
+                    self._wifi_quality_monitor_thread = None
+                    self.logger.info("[WiFi Monitor] 已停止后台监测线程")
     
     def _quality_monitor_loop(self):
         """