The dialog now lists the songs it would rebuild, all ticked, each with when
it was last built and whether that was a rebuild, so songs already rebuilt
by hand can be unticked. GET /api/rebuild-all returns that list, so the
page no longer repeats the server's rule for which job stands for a song,
and POST takes the ticked job ids. A selected job that has since been
rebuilt is reported as skipped rather than rebuilt twice.
When an update improves a stage, existing songs only pick it up when each
is rebuilt from that stage. POST /api/rebuild-all queues an ordinary
rebuild with unchanged inputs for the current job of every song: jobs that
were themselves rebuilt are skipped, as are songs still in progress and
songs whose upload is gone when the stage is acquire. The sidebar button
opens a dialog to pick the stage and confirm the count.
branderson