Define policy for AI generated contributions and discussions

As discussed in a working group meeting, the community may benefit from guidelines surrounding contributions and engagement that occur prominently using AI.

Questions to consider:
- Do we require users to disclose if a significant portion of the contribution was generated using AI?
- Do we require engagement on slack and PRs to be predominantly human generated?
- How can we differentiate between AI and human contributions?
- What are maintainers' rights when it comes to dealing with these contributions and engagements?

Start with the working group discussion referenced in the issue and review the four questions about disclosure, human-generated engagement, identification, and maintainer rights. Done means producing an agreed policy that addresses those questions and can be adopted by the community; no files or tests are named in the issue.

Written by the indexing model from the issue text.