ADR-0087 exemption (no-migration-prescription): no key of any schema is added, removed or re-shaped and no stored row is read differently, converted or dropped: the narrowing is one runtime refusal at one door, for one kind of base, whose remedy is that no pair exists to create; the existing pairs and the overrides in them stay served exactly as before. The retyped exports are runtime functions with no metadata surface, and the compiler names every caller that has not passed the new argument, so there is nothing for `objectstack migrate meta` to rewrite.