escalate_up had composes=() and no source-status guard, so a PM could
escalate a COMPLETED/CANCELLED task and apply_escalation set it back to
BLOCKED — bypassing the state machine's terminal-state invariant.
Defense in depth:
- spec: add PRECONDITION_NON_TERMINAL to escalate_up's extra_preconditions so
the lifecycle gate rejects terminal tasks (invalid_state) before the
journal:decision write fires; generalize _check_intent_preconditions to
honor non-tracing rejection_kind (not_authorized / invalid_state).
- service: apply_escalation (the single write primitive) returns False and
refuses to mutate a terminal task — covers the HTTP escalate route which
bypasses the spec gate. escalate() / escalate_up_to_role() return None on
refusal so the gateway emits a clean invalid_state envelope.
- route: the HTTP escalate route 409s a terminal task BEFORE sending the
escalation notification (so a finished task isn't yanked back, PM not pinged).
Renn F
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