docs :Technical documentation in chinese

I am a developer from China. I translated the [technical documentation](https://google.github.io/A2A/#/) in chinese, but I can't find the git address of the documentation, so I don't know where to pull request.
I am really looking forward to the development of A2A and hope to make more contributions in the future. Thank you for creating such an exciting project!

Find the repository hosting the technical documentation at https://google.github.io/A2A/#/. Look for a 'docs' folder or a separate documentation repository linked from the main A2A project. Once located, submit the Chinese translation as a pull request to that repository. The work is done when the translated documentation is integrated.

索引モデルが issue の本文から書いたものです。