Add stale_closed_issues_days config option to metadata.json:
- 0 (default): Check disabled - repos keep unlimited beads
- >0: Enable check with specified day threshold
Design philosophy: Time-based cleanup is a crude proxy for the real
concern (database size). Disabled by default since a repo with 100
closed issues from 5 years ago doesn't need cleanup.
Also adds a warning when check is disabled but database has >10,000
closed issues, recommending users enable the threshold.
Co-Authored-By: SageOx <ox@sageox.ai>
Executed-By: beads/crew/emma
Rig: beads
Role: crew
27d6a8c2da