A delete landing while a push read YouTube left a plan over no items, so the push emptied the
YouTube playlist a local-only delete keeps: the push now stops at a vanished list (PlaylistGone,
404), and a delete is refused while a sync of the list runs. The closing baseline fingerprints the
title YouTube got, not the one its lock re-reads, so a rename made during the writes stays dirty.
The other-tab test helper bounds its lock wait, so a lock-order regression fails instead of hanging.