ADR-0087 exemption (no-migration-prescription): A runtime narrowing of which notification writes the engine accepts, not a metadata change. No spec key, authorable spelling, export, option, config field or stored shape is added, removed, renamed or re-shaped, and no stored row is rewritten: rows already stored with organization_id NULL keep it until the v18 ownership ceremony attributes them, which already lists sys_notification with the attribution fate. The only type change is an additive optional `organizationId` on the input of `ApprovalMessagingSurface.emit`, the approvals service's messaging surface: the interface is not listed in the package index, but it is published surface, reachable through the exported `ApprovalServiceOptions.messaging` and the public `ApprovalService.attachMessaging`, so it is an additive widening that no existing implementation has to change for. The other categories are closed on facts: the four packages publish (not unpublished); no ADR-0087 id covers notification ownership and this diff adds none (not registered / already-registered); nothing is removed or narrowed on an interface or type (not runtime-interface-only / type-surface-only); and no runtime export is retired (not runtime-export-retired).