📝 clarify AI/LLM policy

[ctcpip]

this was never intended to cover code contributions; this PR makes this explicit to disambiguate

[linusg]

It's not clear how spec text contributions are covered after this change.

[bakkot]

This WFM but if we're intending not to forbid LLM-authored code then it would be nice to require disclosure in any PRs submitting such code.

[ctcpip]

The point of this PR is not to change any policy, it's to clarify. We can later talk about spec text, code, etc. but KG was very clear regarding what this policy was meant to address. Code was explicitly not in scope. Spec text specifically did not come up.

My strong preference is to not gate this PR on questions the committee has not considered. The current language is inaccurate in that it is much broader than intended and we should not equate its ambiguity with actual committee policy. My proposal is that here we should make the minimal change necessary to clarify.

[ryzokuken]

Phrasing LGTM, no comments on the actual position.

[bakkot]

I definitely did intend for this to cover spec text, although it didn't come up. I'm OK with landing as is as long as we come back to clarify later though.