refactor(config): 重构配置系统和MQTT相关功能

移除状态发布功能，简化配置系统
更新MQTT配置和主题设置
调整README文档以反映最新变更

src/config.cpp

@@ -3,25 +3,29 @@
 namespace custom {
 
 void CustomConfig::loadDefaults() {
-    network_interface = std::string(NETWORK_INTERFACE);
-    mqtt_broker = std::string(MQTT_BROKER);
+    // Network settings
+    network_interface = NETWORK_INTERFACE;
+    mqtt_broker = MQTT_BROKER;
     mqtt_port = MQTT_PORT;
-    mqtt_username = std::string(MQTT_USERNAME);
-    mqtt_password = std::string(MQTT_PASSWORD);
-    mqtt_client_id = std::string(MQTT_CLIENT_ID);
+    mqtt_username = MQTT_USERNAME;
+    mqtt_password = MQTT_PASSWORD;
     
-    topic_prefix = std::string(TOPIC_PREFIX);
-    topic_cmd = std::string(TOPIC_CMD);
-    topic_state = std::string(TOPIC_STATE);
+    // Topic settings
+    topic_prefix = TOPIC_PREFIX;
+    topic_cmd = TOPIC_CMD;
+    topic_state = TOPIC_STATE;
+    topic_heartbeat = TOPIC_HEARTBEAT;
+    topic_response = TOPIC_RESPONSE;
+    topic_error = TOPIC_ERROR;
     
+    // Robot control settings
     control_frequency = CONTROL_FREQUENCY;
-    state_publish_frequency = STATE_PUBLISH_FREQUENCY;
+    
+    // Safety settings
+    command_timeout = COMMAND_TIMEOUT;
     max_linear_velocity = MAX_LINEAR_VELOCITY;
     max_angular_velocity = MAX_ANGULAR_VELOCITY;
     emergency_stop_timeout = EMERGENCY_STOP_TIMEOUT;
-    stand_height = STAND_HEIGHT;
-    default_gait = static_cast<int>(DEFAULT_GAIT);
-    
 }
 
 } // namespace custom