ADR-0087 exemption (no-migration-prescription): A validity narrowing at one runtime write door over existing keys: no key of `ViewSchema` or of any other metadata schema is removed, renamed or re-shaped, so there is no tombstone and nothing mechanical for `objectstack migrate meta` to rewrite. Whether the refused container was meant as a member of the container that already expands that name, or as a view item of that name, is authoring intent no conversion entry can decide. New saves are refused with the remedy; a row stored before this change keeps its bytes and is served as before, and no stored row is re-saved. The census found no packaged container that can reach this door in this shape (the source registrars file a container under its object and refuse a `name` that disagrees with it; the thirteen `defineView` sites in this repository carry no top-level `name`), no seeded `sys_metadata` view rows in the example apps, and no Studio or in-repo AI writer that saves a container under a name another container expands unless its author types that name (Studio's generic metadata editor saves a body under the name it carries); hosted tenants and the cloud AI author were not measured. The other categories are closed on facts: the package publishes (not unpublished); no ADR-0087 id covers this rule and this diff adds none (not registered / already-registered); and the change narrows what a runtime write door accepts, not a runtime interface or a type surface alone (not runtime-interface-only / type-surface-only).