doc: add AI policy h/t @dch

Adapted from https://reviews.freebsd.org/D50650

Author: janl

CONTRIBUTING.md

@@ -302,6 +302,19 @@ hub checkout link-to-pull-request
 meaning that you will automatically check out the branch for the pull request,
 without needing any other steps like setting git upstreams! :sparkles:
 
+## Artificial Intelligence and Large Language Models Contributions Policy
+
+The CouchDB project has a long-standing focus on license compatibility, and
+appropriate attribution of source code. AI and LLMs, by their nature, are unable
+to provide the necessary assurance, that the generated material is compatible
+with the Apache 2 license, or that the material has been appropriately
+attributed to the original authors.
+
+Thus, it is expressly forbidden to contribute material generated by AI, LLMs,
+and similar technologies, to the CouchDB project. This includes, but is not
+limited to, source code, documentation, commit messages, or any other areas of
+the project.
+
 ## Thanks
 
 Special thanks to [Hoodie][#gh_hoodie] for the great