pin_target_not_pinned· reason_code· applies to event_envelope, state_resolutionSub-reason for failed_precondition when ak.pin.reorder addresses a (pin_scope, target_ref) that has no causally earlier surviving ak.pin.add assertion to inherit note and the remaining entry fields from. Reducers MUST NOT synthesize a rank-only entry that would put the target back into the roster. See zh/models/pins.md section 4.