fix(DBNMQTTool): paho-mqtt disconnect 回调签名兼容 v1/v2

- _on_disconnect: 用 *args 兼容 v1(3参数) 和 v2(5参数)
- Client 构造加 callback_api_version=VERSION2
- _on_connect 签名保持不变 (v2)

DBNMQTTool/dbn_mqtt_tool/mqtt_client.py

@@ -68,7 +68,6 @@ class MqttClient:
             self._connected = True
             self._notify_status(True, "已连接到 Broker")
 
-            # 订阅所有设备的上报 topic
             from .protocol import (
                 TOPIC_ALL_CONFIG_RESP, TOPIC_ALL_DATA_LOOP,
                 TOPIC_ALL_DATA_EVENT, TOPIC_ALL_STATUS
@@ -81,7 +80,7 @@ class MqttClient:
             self._connected = False
             self._notify_status(False, f"连接失败 (rc={rc})")
 
-    def _on_disconnect(self, client, userdata, flags, reason_code, properties=None):
+    def _on_disconnect(self, client, userdata, *args):
         self._connected = False
         self._notify_status(False, "已断开连接")
 
@@ -107,6 +106,7 @@ class MqttClient:
         self._client = mqtt.Client(
             client_id=client_id,
             protocol=mqtt.MQTTv311,
+            callback_api_version=mqtt.CallbackAPIVersion.VERSION2,
         )
         if self._config.username:
             self._client.username_pw_set(self._config.username, self._config.password)