Adding integration for IBM's ACP and Google's A2A

[tituslhy]

I think it's great that LangChain has native integration with MCPs. With the advent of agent interoperability protocols such as IBM's Agent Communication Protocol and Google's A2A protocol, it will be great if LangChain has native adapters to those as well.

I've written my own code which ultimately concerts agent servers (either A2A or ACP) into tools wrapped to a LangGraph react agent but I'm not sure if that's the best way to do it.