- RunMigrations applies versioned SQL files via golang-migrate + embed.FS (iofs)
- ErrNoChange handled correctly - not treated as failure
- Migration 0001 creates full current schema with CREATE TABLE IF NOT EXISTS
- All three tables (updates, tags, tag_assignments) with acknowledged_at and ON DELETE CASCADE
- Uses database/sqlite sub-package (modernc.org/sqlite, no CGO)
- go mod tidy applied after adding dependencies
