nx_portability_proof_census.nx

nx_portability_proof_census.nx -- the EMIT-PROVEN tier of the HAL reach census. AUTHOR=ORGAN, measured, no-wave: nx_portability_census proves each backend FILE EXISTS (= reach, 16/16). This sibling proves the stronger claim that census header itself flags as the gap -- that the backend actually EMITS CORRECT NATIVE code, KAT-verified -- by COMPUTING, per ISA, whether a real GREEN gate-log / parity-stamp exists. It reads portability_proof_sources.tsv (WHERE the proof lives + WHICH token = GREEN) and VERIFIES the token actually occurs in that file (does NOT trust the map's say-so): a row whose token is absent reads UNPROVEN. proven_permil <= reach_permil by construction; the delta IS the rv64-only kernel-emitter foundation gap, now a tracked number that ratchets UP as per-ISA emit KATs land (twin of nx_hal_purity_audit's ratchet). Self-validating: a POS control (real GREEN token) MUST read proven; a NEG control (bogus token in the same real file) MUST read unproven -- so the census cannot rubber-stamp. Writes portability_proof_census.tsv + an honest PROOFGATE verdict to the log. license_tier: ORIGINAL