-- Index the crashed-worker-recovery arm of the job lease predicate.
--
-- lease/lease_kinds match:
--   WHERE (state = 'pending' OR (state = 'running' AND leased_until < now()))
-- crawler_jobs_ready_idx (0016) is `ON (scheduled_at) WHERE state = 'pending'`,
-- so it covers only the pending arm. The `state = 'running' AND leased_until`
-- arm had no usable index, so Postgres could not BitmapOr the two arms and
-- degraded to a sequential scan of the ENTIRE crawler_jobs table — including all
-- done/dead rows not yet reaped — on every lease poll, by every worker,
-- continuously (audit H2, the headline performance finding).
--
-- A partial index on leased_until over just the running rows makes the recovery
-- arm index-backed. `state = 'running'` is an immutable predicate (now() stays
-- in the query, not the index). The running set is tiny (in-flight jobs only),
-- so the index is cheap to maintain.
CREATE INDEX crawler_jobs_running_lease_idx
    ON crawler_jobs (leased_until)
    WHERE state = 'running';