nx_probe_ub_shift.nx

nx_probe_ub_shift.nx -- MUST-REFUSE WITNESS (UB axis rung 1, 2026-08-13): a CONSTANT shift count outside the result width. MEASURED pre-fix: `1 << 70` compiled clean, ran, and returned 64 -- the processor keeps only the low 6 bits of the count (70 -> 6), so the program silently computed a different shift than the one written. Decidable at compile time. EXPECT: COMPILE-FAIL naming the range + capability=shift-count-range. (A RUNTIME count is deliberately NOT checked here -- that is the honest C-class lane and its own rung; the control in the gauntlet proves a variable count still compiles.)