bae9f8ab85
The salvaged commit only swept `hermes-sync-back-*.tar`. The extraction staging dir (`tempfile.TemporaryDirectory(prefix="hermes-sync-back-")`) is leaked by the same hard kill, so the sweep now reclaims both shapes and returns the count. The window drops from 24 h to 6 h (the reporter's value): archives appear every few minutes on a busy gateway and a live transfer is never hours old. Tests trimmed to two invariants: the sweep touches only stale prefixed entries, and a real sync_back reclaims a leaked archive while writing its own tar under the identifiable prefix.