Delete orphaned Garage objects (cleanup) #202
Description
From ADR-083 Phase 9 - future enhancement.
When artifacts are deleted, Garage objects may become orphaned if deletion fails partway through.
Task:
- Add cleanup logic to artifact_cleanup_worker.py
- Scan for Garage keys not referenced by any artifact
- Delete orphaned objects older than N days
Related: api/api/workers/artifact_cleanup_worker.py