A CREATE INDEX CONCURRENTLY that fails half-way leaves an INVALID index,
and the migration re-run after migrate resolve --rolled-back finds it
through IF NOT EXISTS and does nothing: recorded applied, with an index
the planner never uses. 0477 has this shape.
The boot now drops an INVALID index that a not-yet-applied migration
builds concurrently before it runs migrate deploy, with a bounded lock
wait, so the re-run builds it again. An INVALID index whose migration is
recorded applied is named on stderr with the rebuild that mends it. The
deploy runbook says both.
