v0.3.0

Added

• prune command to delete old closed tickets
  • --days=N to set age threshold (default: 7 days)
  • --all to prune regardless of age
  • -f/--force to actually delete (dry-run preview by default)
• closed_at timestamp field set when tickets are closed
• Dependency protection: closed tickets referenced by open/in-progress tickets are never pruned

Fixed

• BSD sed compatibility in update_yaml_field (was GNU-only)
• update_yaml_field now uses more robust first-line substitution for new fields