nx_apistack_slo_gate.nx

nx_apistack_slo_gate.nx -- hermetic gate for CAP-API-SLO. Proves allowed-errors, budget, breach detection, and availability permil. expect_exit: 0 MIGRATED 2026-07-31 onto nx_gate_verdict (D001, ws=gate-dry-d001). Teeth UNCHANGED -- same four checks, same predicates, same constants, same exit contract. Retired: the private gp/gn printers and the private pass/fail counters, plus the else-ladders that existed only to print a bespoke failure string. The check names are carried into gv_check so no domain detail is lost (rule 25: rewrite better, never strip). Proven by nx_gate_migrate verify (judge-equivalence), not by byte-equality.