docs: add no-AI/LLM policy to CONTRIBUTING.md as well

 CONTRIBUTING.md | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 641d81b..cc2ac04 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -11,6 +11,12 @@ You'll likely have more success with your contribution if you visit
 [#river](https://web.libera.chat/?channels=#river) on irc.libera.chat to discuss
 your plans first.
 
+## Strict No LLM / No AI Policy
+
+Use of generative AI/LLMs is strictly forbidden for all contributions to river.
+
+This includes bug reports and comments on the issue tracker.
+
 ## Commit messages
 
 Please take the time to write a good commit message, having a clean git