Ability to customize prompt

Good spot and good shout - yeah prompt management would be great + I never considered the one-to-one relationship possibility, not sure how I missed that :)

This MR should handle both. It works already and has update hook (but backup first in case).
Needs work because I haven't done phpcs & automated test updates to coorrespond with this yet.

But what it does:

1. Adds an AI Auto-reference Prompt entity type
2. Let's you select that entity type from the node bundle config page
3. Uses that as the prompt instead
4. Creates 2 default prompts in update hook (one for multiple, one for single)
5. Improves the default prompts to give the LLM examples of how to reply
6. Sets existing configurations to use the default for multiple (maintains status quo), but then you can subsequently edit to choose the default for single

If you have a moment to help test would be much appreciated

Which one to four of the following

The idea of the two to four was more like telling the LLM it does not need to actually find 4 if there are not 4 relevant ones. You can check out the new default I set for single here https://git.drupalcode.org/project/ai_auto_reference/-/merge_requests/8/... which works for me at least with openai 4o-mini in testing

Automatically closed - issue fixed for 2 weeks with no activity.