-- #239: §5.7's 30-day attention window runs from the failure, but only
-- grabbed_at existed, so a torrent that stalled past the window and then
-- hard-failed at import was born outside it. failed_at records the moment
-- the grab entered 'failed'. Existing failed rows get grabbed_at as the
-- best available approximation.
ALTER TABLE grabs ADD COLUMN failed_at TEXT;

UPDATE grabs SET failed_at = grabbed_at WHERE state = 'failed';