first commit

include/app_config.hpp

@@ -57,6 +57,10 @@ struct MQTTConfig
     std::string username;
     std::string password;
     int keep_alive;
+
+    int qos = 1;               // 默认 QoS 级别
+    bool clean_session = true; // 默认 clean session
+
     VehicleMQTTTopics topics;
 };