/** shutdown forensics — opt-in (`SEMA_DEBUG_SHUTDOWN=1`) stderr trace of every
 *  teardown kill/reap action. stderr lands in the host's engine log, so a "who killed my process"
 *  hunt no longer dead-ends at the drain marker with zero shutdown-phase evidence (test-line pain,
 *  three times — the reap lane was the blind spot of the first cut).
 *  Zero default noise. Single source: the exec env's kill paths AND the task registry's reap paths
 *  ride this one function, so the flag can never half-cover the kill surface again. */
export declare function shutdownDebug(msg: string, extra?: Record<string, unknown>): void;