nx_x86_kat_gate.nx

nx_x86_kat_gate.nx -- SOVEREIGN x86_64 backend run-KAT gate (the gold per-ISA emit-proof tier, hardware-rung-up, NO gcc / NO qemu / NO external binutils). AUTHOR=ORGAN, no-false-green: the proof that nxc2's x86_64 backend EMITS CORRECT NATIVE code is a RUN, not a structural guess. This gate composes the team's own toolchain end to end -- it forks _offc/nx_sov_build_run.elf (nx_cc_sovereign -> nxasm_x86 -> execute) on two KAT modules and reads their real process exit codes: POS nx_emit_kat -> 42 (all three distinct KATs 37/10/81 computed correctly by the backend) NEG nx_emit_kat_raw -> 37 (raw kat(7,5); proves the gate reads the ACTUAL exit, not a baked 42) GREEN iff pos==42 AND neg==37 AND pos!=neg (distinct => no constant rubber-stamp). This is the SOVEREIGN replacement for the external bench-parity / qemu proof: the whole trust path is Nishi organs. Other ISAs reuse this shape, swapping the native run for their sovereign emulator (nx_emu_rv64/arm64/mips64/ppc64le/loongarch64/sparc64). Writes knowledge/status/x86_64_kat_gate.log so nx_portability_proof_census can credit x86_64 as SOVEREIGN-run-proven. license_tier: ORIGINAL