nx_gatekit_runner_gate.nx

nx_gatekit_runner_gate.nx -- THE BOUNDED RUNNER MUST REPORT A KILLED OR CRASHED SUBJECT AS A FAILURE. MEASURED 2026-08-18 (lane B, first trial of nx_gate_roster_run over the deployed-dark gates): 1787075461 trial nx_activities_gate GREEN exit=0 ms=60443 1787075522 trial nx_doctor_apply_gate GREEN exit=0 ms=60018 Both were KILLED by gk_run_cap3's 60 s watchdog and journaled as GREEN, because the runner returned wait_exit_code(status) = (status>>8)&0xFF, which is 0 for a child that died by signal. gk_run had the same hole, so a SEGFAULTING subject read as a pass through every gate built on the kit. ★★★★★★ A WATCHDOG-KILLED SUBJECT THAT RETURNS THE EXIT CODE OF A CLEAN ONE TURNS EVERY TIMEOUT INTO A PASS -- BOUNDING THE WAIT WITHOUT REPORTING THE KILL IS HALF A FIX, AND THE MISSING HALF READS GREEN. The fix is one helper in the base lib (gk_wait_code: 128+signal when the child died by signal) used by both gk_run and gk_run_cap3. This gate is its bite proof, and it uses ITSELF as the subject (`--as-subject <mode>` re-execs /proc/self/exe) so it needs no fixture on disk. TEETH: exit0 -> 0 . exit5 -> 5 . self-SIGKILL -> 137 . a 3 s sleeper under a 500 ms bound -> 137 within 2.5 s . captured output of a clean subject still arrives . BITE: kill fires (rc != 0) on the sleeper and is silent (rc == 0) on the clean subject. license_tier: ORIGINAL No hw writes (Rule 26). expect_exit: 0