nx_quality_grade_test.nx

nx_quality_grade_test.nx -- smoke: synthesize a tiny Module IR and grade it via every Layer-0 rule. Asserts: license_tier: ORIGINAL 1. Sealed-enum validity predicates accept all in-range values and reject out-of-range. 2. A clean synthetic Module (1 main function, 0 BR_COND, 5 instrs, no dead funcs) grades A. 3. A messy synthetic Module (1 function with CCN > 25, 1 dead function) grades D or worse. 4. The grader correctly counts findings per category. We hand-build Module + Function structs in mmap'd memory instead of running the self-host parser. This isolates the grader logic from any parser bugs and lets the smoke run in milliseconds.