nx_planepeek_gate.nx

nx_planepeek_gate.nx -- THE REFEREE FOR nx_planepeek's FALSE-ABSENCE FIX (debt 1787282525). WHAT IS UNDER TEST. v1 of nx_planepeek printed one word -- MISS -- for five distinguishable conditions, and that word is a NEGATIVE ASSERTION about a plane. It was quoted as proof of absence in a build-refusal message and nearly produced a filed defect against a healthy lane. The fix gives every condition its own word and its own exit code, and prints the coverage each verdict was computed from. THIS GATE PROVES THE SEPARATION IS REAL, IN BOTH DIRECTIONS. WHY IT IS END-TO-END. The defect is in what the ORGAN PRINTS AND EXITS WITH, not in a pure function, so the only honest subject is the built ELF. It is forked with tr_run_capture (the one proven subprocess primitive) and judged on exit code AND emitted bytes. ★A GREEN THAT NEVER HAD A CORRESPONDING RED IS UNVERIFIED, so the decisive teeth are gv_bite pairs: the same organ must FIRE on the broken fixture and stay SILENT on the healthy one. Two tests that each isolate one signal do not prove discrimination between them. ★A READER THAT MISSES EVERYTHING WOULD PASS EVERY ABSENCE TEST -- hence the POSITIVE CONTROL (tooth 2/3): a key that IS present must be found, with its bytes. Without it, an organ that returned MISS unconditionally would score full marks on this gate. ★ASSERT THE FIXTURE REACHED THE CONDITION BEFORE ASSERTING THE OUTCOME: tooth 1 refuses to believe any verdict until the subject has actually run and reported scanning segments>0. FIXTURES ARE ASSEMBLED AT RUNTIME under /tmp/<gate>/ (never the production knowledge/store tree: a gate sharing a fixture with a production beat reports on the FIXTURE, not the code) and the setup is IDEMPOTENT -- every artifact is unlinked before it is written, because a gate that is not idempotent reports on its first run and lies about every run after. license_tier: ORIGINAL Read-only outside /tmp. No hw writes (Rule 26).