add sening functions

wangzhibo

2026-08-26 70481429367ca00144b24f118cbfdfb28b02967d

 xiaozhi-esp32-2.2.6/main/protocols/protocol.h

@@ -73,6 +73,7 @@
    virtual void SendStopListening();
    virtual void SendAbortSpeaking(AbortReason reason);
    virtual void SendMcpMessage(const std::string& message);
    virtual void PrepareForNetworkStandby() {}

protected:
    std::function<void(const cJSON* root)> on_incoming_json_;