Add issue auto-assign and self unassign feature #5344
Description
Add a feature so contributors can self-assign and unassign issues, with a limit on how many issues one person can hold at a time.
Why this is useful
- Prevents contributors from taking too many issues and not finishing them.
- Keeps issues moving and more fairly distributed.
- Reduces manual work for maintainers who currently assign/unassign people.
Edge Cases to Handle
- Cannot self-assign if they’re the issue creator.
- Cannot assign if already assigned to the maximum number of issues.
- If an issue is already assigned to someone else, they shouldn’t be able to override it.
- If a contributor closes or completes one of their issues, that slot should automatically free up.
- Optionally, maintainers/admins can still manually assign/unassign anyone as needed.