failMissingTarget failed the delivery as the batch had read it, so a
delivery a worker sent and let go between the batch read and the
ownership check could end failed after a successful attempt. It now
reads the row once it owns the delivery and fails it only if the
status is still the one the batch read, as processNewTask does. A row
that cannot be read is left alone.
TestSweepPending_TargetDeleted now checks that the first sweep already
queues the healthy delivery and the second does not queue it again.
Model: opus-5-5