The Plex playlist's reorder is a dnd-kit drag, and neither of its sensors activates under jsdom,
so `commit()`'s failure path could not be reached from a test. The query, the optimistic copy and
the two writes (reorder, remove) move into `usePlexPlaylistEdits`, unchanged, and are driven
directly: a failed reorder is said and the rows go back; an accepted order lands in the detail
cache; a failed removal comes back.
It also settles the `putBack` question that could not be driven before: with the refreshed list
taken in BEFORE the reorder fails, a rollback bound to the render that started the reorder puts a
removed row back, and the deep-equal refetch never clears it. The live cache read the code has now
is what keeps it out; the test fails if it goes back to the closure's `q.data`.
peter
946c8f26db