Add GitHub Action to detect and flag low effort PRs

[AarishMansur]

During GSSoC I have seen lots of low effort PR and clearly AI generated with no real understanding of the codebase. This wastes maintainer review time so I propose A GitHub Action that runs on every PR and checks for basic quality signals like:

• PR description is too short or not filled properly
• Commit messages are vague like "fix" or "update"
• No linked issue

If a PR fails these checks the action will auto comment asking the contributor
to improve it and add a label like needs-more-detail

but i dont think auto closing will be added in this github action because it can feel harsh for genuine beginners so starting with a comment and label is better. Maintainers can still manually close if needed.

We already have CI builds and typechecking so this just extends what we have.
Happy to work on this if the idea gets approved.

[AarishMansur]

@magic-peach would love to hear your opinions on this