nx_backend_audit_test.nx

nx_backend_audit.nx -- self-host substrate audit, written IN NishiLang. Per user 2026-05-20: "we arent building lints off of nishi we are nishi from bits up". The substrate audits itself using its own file I/O + byte-search primitives. No bash, no grep, no awk -- the lint runs as a NishiLang program compiled by the same compiler it audits. Three substrate-honest audits in one program: A. Sub-word load zero-extend audit (was bash). Scans backend ctx files for `_emit_load_(byte|word|dword)_signed`. B. Syscall translation table audit (was bash). Asserts every SYS_X used in nx_syscalls.nx has a corresponding `if num ==` entry in the x86_64 translation table. C. Call-arity overflow audit (was bash). Asserts parser parse_primary_call has a die path for n_args overflow. Each audit emits one line to stderr: name + PASS/FAIL. Exit code = sum of (1 per failure). Exit 0 == all PASS. license_tier: ORIGINAL lineage_id: nishi_backend_audit_q10