ADR-0087 exemption (no-migration-prescription): Nothing authorable is renamed, retired or re-typed: `sys_user_position.position` stays a `Field.text`, every object key and every stored row parse exactly as before, and no stored assignment is rewritten or refused on read, so `objectstack migrate meta` has nothing to act on. What narrows is the ACCEPT SET of one runtime write path: a non-system insert, or an update that changes `position`, whose value names no `sys_position` row in the writer's organization or among the organization-less rows is refused `400 VALIDATION_FAILED` with the envelope the row's sibling lookup columns already answer with. The refusal text names the value and its own fix, and the measured in-repo and consumer writers (hotcrm, hotclm) all write catalog names, so there is no document for a migration to act on.