A cleanup that waited from an earlier move never names a key folder the
new move just filled, so moving back keeps the previews. Removing empty
folders walks top-down and never into a link or junction. Any error
while copying undoes the copies; once the switch is committed, a journal
that cannot be removed no longer undoes it. Hand-edited cleanup entries
and marker keys never name a folder outside the stores; removal stops at
interpreter exit. The path field carries aria-invalid with its reason,
and a review that went stale reviews again.