nx_fabric_flow_gate.nx

nx_fabric_flow_gate.nx -- LIVE GATE for R1 of the SkyHammer fabric exceed ladder. Proves the §7 acceptance spec mechanically: a credit-controlled link (R1, composing nx_h2_flow) is LOSSLESS + latency-BOUNDED under a burst that makes an uncontrolled baseline drop heavily -- with three NEGATIVE CONTROLS so the result cannot be rigged. criteria (all must hold): 1 R1 overflow-drops == 0 (lossless by construction) 2 baseline drops >= 5% of N (the burst genuinely overloads -- non-vacuous) 3a R1 p99 latency <= 3*(B/D) (bounded / deterministic) 3b NC2 (lossless-uncontrolled) p99 >= 3 * R1 p99 (R1 escapes the loss/bloat tradeoff) 4 R1 goodput >= baseline goodput (no throughput sacrifice) negative controls: NC1 credit bookkeeping w/o the backpressure gate -> drops RETURN (the GATE is the cause) NC2 buffer >= N (no real bottleneck) -> baseline drops VANISH (bottleneck is real) NC3 every run still delivers all N (drops counted at the buffer, independent of delivery) expect_exit: 0 license_tier: ORIGINAL