Make agentic a2a compliant

[drbrady8800]

Make the Agentic API a2a compliant following this guide.

Specs: https://google-a2a.github.io/A2A/latest/specification/
Tutorial: https://google-a2a.github.io/A2A/latest/tutorials/python/1-introduction/

[scottpersinger]

The real spec is here: https://google-a2a.github.io/A2A/specification/

Bonus points for sending the spec and our api.py file to Claude and having it generate the A2A server!