- Implemented question auto-close scheduling with configurable enablement, delay, and scan interval.
- Added reaction lookup and issue-close operations across backend, proxy, and client APIs.
- Extended host tools and app server wiring to append auto-close suffixes, run scheduler, and cancel closures.
- Updated documentation and env examples with question-autoclose settings and behavior notes.
- Added pending_closures persistence and lifecycle handling to claim, finalize, requeue, and cancel rows.
- Added tests covering scheduler, DB, proxy, server, and host-tool cancellation scenarios.