What one cleanup pass did, or would do under --dry-run. Garbage
collection has to be reportable to be trustworthy: every list here is
something that disappeared (or would).
Whether per-branch teardown may run this resource’s cleanup hook at all.
Ownership decides, not the presence of a command: a user-owned pnpm
store with a cleanup command must still survive newgit remove.
Workspace directories under workspace_root that no binding record
claims. A workspace is a cache, so an unclaimed one is just garbage —
but only the records can say which ones are claimed.