ADR-0087 exemption (no-migration-prescription): Nothing authorable is removed, renamed or re-typed at runtime: no spec key, no export, no stored row moves, and every view body parses byte-identically, so `objectstack migrate meta` has nothing to reach. The only thing that moved is a TypeScript annotation, whose channel is the consumer's compiler. `type-surface-only` does not apply because this diff touches `packages/spec/**` (its predicate 2).