Introduce an initial LLM Usage Policy

Driven by our prior discussion, this lays out an initial policy which is
meant to be simple to understand.

After consideration, and in particular looking at the current `pip`
contribution policy[^1], I have taken us back to the original two
"columns" I suggested for our policy: "Disclosure" and "Ownership".

The policy is stated as meant for "LLM Generated Contributions". Although
during earlier discussion I suggested that we avoid singling out these
tools, on review (especially with some recent PRs), I am not sure that is
wise. I would like it to be very clear to LLM users that we have some
additional standards for them -- which I view as offsetting the ease with
which they can spam projects and do harm.

The policy states that it is "to protect our maintainers as well as
our contributors"; hopefully this is a clear hint that the maintainers
even _need_ some level of protection, and will help new contributors
understand why we have a policy.

Echoing some prior discussion about "Don't let AI speak for you" /
"Don't let AI think for you", there's a line included that draws a
distinction between "typing" and "thinking".

To give us a clear out, in case we have truly problematic github users
show up, the policy calls out "extreme cases" as spam/slop.

Finally, the policy itself links back to the original discussion as an
open invitation for anyone who wants to advocate for us refining this
policy.

[^1]: It's very short.
      See: https://pip.pypa.io/en/stable/development/contributing/

Author: sirosen

CONTRIBUTING.md

@@ -19,6 +19,25 @@ documentation corrections or contributions that do not change pip-tools itself.
 
 Contributions following these guidelines are always welcomed, encouraged and appreciated.
 
+### LLM Generated Contributions
+
+Although contributors are free to use whatever tools they like, `pip-tools` has a policy regarding LLM contributions to protect our maintainers as well as our contributors.
+
+1. **Disclosure**: contributors should indicate when they have use an LLM to generate a part of their work.
+   You may also be able to help maintainers understand what they are looking at by sharing how you used a tool, e.g. what prompts you used.
+
+2. **Ownership**: it is the contributor's responsibility to understand submitted code and ensure, to the best of their ability, that it meets project standards.
+   In particular, contributors need to be prepared to discuss their changes during review.
+
+Overall, our position is that an LLM may do the _typing_ for you but it should not do the _thinking_.
+
+:::{caution}
+In extreme cases, slop PRs may be closed as spam.
+:::
+
+_The [rationale and discussion](https://github.com/jazzband/pip-tools/discussions/2278) behind this policy is open and public. Feel free to raise new issues or make suggestions there._
+
+
 ## Project Release Process
 
 Releases require approval by a member of the [`pip-tools-leads` team].