sys_migration already carries app_code; sys_menu and sys_api did not, so
nothing said which application seeded a row - which is what an uninstall or
an audit would have to ask.
The migration adds the columns through the runtime models rather than
cmd/migrate/migration/models, whose frozen ModelTime is wrong for anything
ordered after the soft-delete conversion.
Claude-Session: https://claude.ai/code/session_01HPTAw8b8tAdFNFn8rKdPYx
