-- Migration 0007: Add checksum column to schema_migrations.
-- This migration is idempotent and safe to re-run.
-- For existing databases (pre-1.0.54): ALTER TABLE adds the checksum column.
-- For fresh databases (1.0.54+): 0001_init.sql now creates the table with checksum column.
-- This migration handles the upgrade path only.

ALTER TABLE schema_migrations ADD COLUMN checksum TEXT DEFAULT '';