-- Apply after 20260909_financial_ledger.sql, before deploying releaseHold changes.
-- Existing released rows stay NULL: their original reason cannot be reconstructed.
ALTER TABLE teacher_withdrawal_holds
  ADD COLUMN release_reason VARCHAR(500) NULL AFTER released_at;

-- Rollback: revert the application writer first. Keep this nullable audit column
-- and any recorded reasons; dropping it would erase financial history.