ADR-0087 exemption (no-migration-prescription): The narrowing is a refusal at the write doors (publish, `os validate`, the marketplace managed install) of item NAMES and of an `overrides` declaration outside the base's paired package: no metadata key, accepted value, export or error code is removed or renamed, and no stored shape changes. The remedy is a rename of an item, or a declaration added in the base's paired `.custom` package, both authoring choices a person makes; there is no mechanical conversion between two metadata versions for `objectstack migrate meta` to apply, and the precondition count on #28410 found no same-named item inside a dependency closure in hotcrm or the repository's examples. The other categories are closed on facts: all three packages publish (not unpublished); no ADR-0087 id is named or touched (not registered or already-registered); the one `packages/spec/**` file touched is the error-code provenance ledger (`api/error-code-ledger.zod.ts`), two rows naming new emitters of the already-registered `NOT_OVERRIDABLE`, so no schema, type or runtime interface moves (not type-surface-only, not runtime-interface-only); and no export is retired (not runtime-export-retired).