snapshot create --prune purged the older snapshots holding a volume's
files when the volume, mounted below a configured path, was not
mounted: its empty mount point read as deleted files.
The scan now records in the local index each directory at or below a
configured path that the walk found an entry in and that, once listed,
is on a different device from its parent; listing mounts an
automounted volume. Under --prune, when an earlier snapshot of that
name recorded such a directory and this run does not, the run skips
the prune, keeps every older snapshot and exits non-zero, naming the
directory. For a volume retired on purpose, snapshot purge removes the
older snapshots.
Model: opus-5-5