Add AI acknowledgement checkbox and welcome comment

[RDaxini]

• Closes Add AI check box to PR template #2617
• I am familiar with the contributing guidelines
• Tests added
• Updates entries in docs/sphinx/source/reference for API changes.
• Adds description and name entries in the appropriate "what's new" file in docs/sphinx/source/whatsnew for all changes. Includes link to the GitHub Issue with :issue:`num` or this Pull Request with :pull:`num`. Includes contributor name and/or GitHub username (link with :ghuser:`user`).
• New code is fully documented. Includes numpydoc compliant docstrings, examples, and comments where necessary.
• Pull request is nearly complete and ready for detailed review.
• Maintainer: Appropriate GitHub Labels (including remote-data) and Milestone are assigned to the Pull Request and linked Issue.

Changes:
Add checkbox to PR
Add workflow to auto-generate a comment on issues and PRs from first-time contributors

Possible:
Automatically assign a label to first-time contributor issues/PRs
Update contributing guidelines with a short note on AI

[RDaxini]

It is also possible for the bot to attribute labels to first-time contributor issues and PRs. Do we want to create a first time contributor label for the bot to assign automatically? Other wording of the label could just be welcome, new contributor, etc.

I think these changes could also be complemented by an update to the contributing docs. Not a full-page discussion, but just a note similar to the message presented in the welcome comment / check box.

[echedey-ls]

Automatic labelling for statistics I guess? The automatic message seems enough of a heads-up for me.

I don't think vibe coders are going through the contrib docs, but it doesn't make any harm to include that extra info as a stance. Maybe one day AI will 'learn' that and stop vibe coders. +1 to that proposal.

Thanks for the ideas and initiative @RDaxini

[echedey-ls]

Suggested change

	guidelines.
	guidelines.

Missing newline at the end (consistency and Git tradition)

[echedey-ls]

Do we really want this? IMO, it's not adding any value to the conversation. Plus, an automated thanks/welcome is less welcoming than anybody of us writing a "Confirmed. Thanks for noticing that @ ...!!" message. More natural.

[RDaxini]

Do we really want this? IMO, it's not adding any value to the conversation. Plus, an automated thanks/welcome is less welcoming than anybody of us writing a "Confirmed. Thanks for noticing that @ ...!!" message. More natural.

I was debating that in my head and then just included it in the end, but I agree with you—a personal welcome from us would be better.

[echedey-ls]

Not needed, probably.

Suggested change

permissions: {}