DOC: Policy on LLM usage

[VeckoTheGecko]

What is your issue?

Hey all. I think it would be really good to have a policy on LLM usage (context #11124 (comment) ).

I've seen core devs here using it with the implicit policy of:

• mentioning when it's been used ("claude came up with ...")
• not using it for interactions / communication on the tracker (e.g. see the CLAUDE.md file)

I think it would be greatly beneficial to codify this in the contributing guidelines so it's explicit. Also to help volunteers decide where to give their time.

Jellyfin has a policy I think is nice and would suit us - though maybe this is something to discuss and decide internally in the core dev team.

(Note: I searched the contrib for notes about AI/LLM usage and didn't find anything - but if I missed it, sorry! I'm on mobile atm and wanted to type this up )

[ianhi]

There is fairly long and detailed discussion over on matplotlib (matplotlib/matplotlib#30848) that might be relevant reading for this.