nx_nv1_gate.nx

nx_nv1_gate.nx -- ENGINEER gate for the NishiLossless v1 container. Evidence-driven, re-runnable, no network: writes a synthetic container (3 PCM chunks of a known ramp + 5 JPEG-stand-in frames), validates it, asserts every count/byte round-trips, then proves the validator REJECTS each malformation class (truncation, bad magic, bad version, bad kind, nonzero-len terminator, trailing bytes, overrun chunk). license_tier: ORIGINAL