Automatically add AI prompts to icalendar commits

[niccokunzmann]

#1312 proposes to add all prompts to the commit messages.
I created https://github.com/pycalendar/ai-prompt-auto-commit to automate this process, currently supporting Claude AI.

This should make it easier for us

• to comply with our AI policy in case of using Claude AI
• guide contributions into the right direction
• provide an example of how to properly comply with the AI policy

See also:

• Update AI policy, per NLnet document. #1312 (comment)
• Use of Claude in PR: deprecate q_join, q_split and foldline for icalendar 8 (#1011) #1314