GitHub action to unassign stale `take`s

### Is your feature request related to a problem or challenge?

#9132 introduced a way for anyone to take issues; I've been going through the backlog and noticed we have some issues where someone does a `take` but then there is no activity for a few months, prompting me to try check with the assigned person if they are still working on the issue.

Ideally want to unassign them if they are no longer working on an issue so another person who might be interested in the issue can take over, or just to make it easier to filter issues which aren't actively being worked on by anyone.

### Describe the solution you'd like

Another GitHub action to remove assignments by `take`s if there has been no activity for a certain period of time (e.g 3 months). Would first need to comment a warning of sorts (similar to the action that marks PR as draft) but actually unassigning them.

Would need some considerations:

- If there is a linked PR open, I guess we can't unassign them since the discussion may have moved to the PR
- Maybe keep it very simple for now: if after a `take` there has been 0 activity from the assignee the action will comment after 3 months asking if this is still active; if 7 days and no reply then unassign them

### Describe alternatives you've considered

Don't do this if this isn't desirable. Some issues may be quite complex and need a lot of time to complete (though maybe we can assume a manual assignment overrides this so they won't get unassigned by the action, only if they were assigned via a `take`)

### Additional context

_No response_

The issue names a new GitHub Action but no files, tests, or existing workflow entry points. Start by reviewing the repository's current GitHub Actions and the existing `take` and draft-PR automation, then clarify how to detect inactivity, linked pull requests, and manual assignments. Done means a warning is posted after the chosen period and the `take` assignment is removed after the reply window when appropriate.

Written by the indexing model from the issue text.