nx_macro_argcap_probe.nx

nx_macro_argcap_probe.nx -- NEGATIVE CONTROL for the >8-argument macro refusal (debt 1785521154). THIS FILE MUST FAIL TO BUILD. It is not a gate; it is the proof that the tooth BITES. The macro below declares NINE parameters. Before the fix, only the first 8 were registered, so the 9th parameter name `i` was never recognised inside the body -- it fell through to the copy-verbatim branch and was emitted as the LITERAL identifier `i`. Because a variable named `i` IS in scope at the call site, that produced a program which COMPILED AND RAN, returning the wrong value (7, the local i) instead of 9. A silent miscompile with no diagnostic. After the fix, lexm_subst REFUSES the whole expansion, emits nothing, and the macro name survives to the parser -- so the build fails LOUDLY with `undefined function: ARGCAP9`. EXPECTED: BUILD-FAILED with an undefined-function error naming ARGCAP9, plus the nx_tokenizer stderr warning naming the argument count. A SUCCESSFUL BUILD MEANS THE FIX REGRESSED. expect_exit: nonzero-build license_tier: ORIGINAL