ADR-0087 exemption (no-migration-prescription): A runtime semantics change of the declared key flow.runAs (both values) after an approval decision, not a metadata shape change. No spec key, enum value, export, option, config field, response field or stored shape is removed, renamed or re-shaped, so there is no tombstone and nothing for `objectstack migrate meta` to rewrite. What narrows is whose rights a runAs 'user' run's nodes after an approval decision carry: the decider's instead of the trigger user's, so a node the decider may not perform is refused where it used to run. A runAs 'system' run keeps its elevation and only its attribution user moves to the decider. The other categories are closed on facts: the three packages publish (not unpublished); no ADR-0087 id covers this behaviour and this diff adds none (not registered / already-registered); and the change is a behaviour change, not only an interface or type change (not runtime-interface-only / type-surface-only).