"The ubuntu-latest label will migrate to Ubuntu 26 beginning October 19, 2026. For more information, see https://github.com/actions/runner-images/issues/14748"

ADR-0087 exemption (no-migration-prescription): A validity narrowing at one runtime write door over existing keys: no key of `HookSchema` 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. What `body` a refused hook should carry 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 no stored row is re-saved (measured: `migrateStoredMetadata({ apply: true })` on a stored hook row with neither field reports it canonical, failed 0, and the bytes are unchanged). The census of writers through this door, taken first at `1db5322ba2`: Studio at the objectui pin (`ab18797215`, unchanged since the census of the handler-only refusal, which read its hook skeleton carrying a `body`); objectstack `examples/**` and `packages/qa/**` seed no `sys_metadata` hook rows (zero `type: 'hook'` items); `os meta register` forwards the author's own file and emits no hook of its own; the artifact, boot and install-local doors never call `saveMetaItem` for a hook (every call site in the tree saves a fixed type other than `hook`, or forwards an author's request: the REST and dispatcher `/meta` saves, `migrateStoredMetadata`, `duplicatePackage`). The only first-party bodies of this shape were test probes (seven suites), which now carry a `body`. Package duplication of a package holding such a row now reports that row as failed with this refusal (measured: copied 1, failed 1, the source rows' bytes unchanged). 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 The other categories are closed on facts: the package publishes (not unpublished); no ADR-0087 id covers this rule and this diff adds none (not registered / already-registered); and the change narrows what a runtime write door accepts, not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).

"The ubuntu-latest label will migrate to Ubuntu 26 beginning October 19, 2026. For more information, see https://github.com/actions/runner-images/issues/14748"