do not allocate memory if old IoT protocol is not used

main/iot/thing.cc

@@ -8,22 +8,30 @@
 
 namespace iot {
 
+#if CONFIG_IOT_PROTOCOL_XIAOZHI
 static std::map<std::string, std::function<Thing*()>>* thing_creators = nullptr;
+#endif
 
 void RegisterThing(const std::string& type, std::function<Thing*()> creator) {
+#if CONFIG_IOT_PROTOCOL_XIAOZHI
     if (thing_creators == nullptr) {
         thing_creators = new std::map<std::string, std::function<Thing*()>>();
     }
     (*thing_creators)[type] = creator;
+#endif
 }
 
 Thing* CreateThing(const std::string& type) {
+#if CONFIG_IOT_PROTOCOL_XIAOZHI
     auto creator = thing_creators->find(type);
     if (creator == thing_creators->end()) {
         ESP_LOGE(TAG, "Thing type not found: %s", type.c_str());
         return nullptr;
     }
     return creator->second();
+#else
+    return nullptr;
+#endif
 }
 
 std::string Thing::GetDescriptorJson() {

main/mcp_server.cc

@@ -30,7 +30,7 @@ void McpServer::AddCommonTools() {
             return Board::GetInstance().GetDeviceStatusJson();
         });
 
-    AddTool("self.speaker.set_volume", 
+    AddTool("self.audio_speaker.set_volume", 
         "Set the volume of the audio speaker. If the current volume is unknown, you must call `self.get_device_status` tool first and then call this tool.",
         PropertyList({
             Property("volume", kPropertyTypeInteger, 0, 100)