nx_regalloc_exec_test.nx

nx_regalloc_exec_test.nx -- PROVE register-allocated execution is 1:1 with the reference, on the race kernel's real arithmetic, over many inputs -- AND prove the check CATCHES a corrupted allocation. This is the gate that makes absorbing the allocator into codegen safe: any g1-style miscompile diverges here and fails. v0=INPUT c, v1=INPUT acc, v2=INPUT i v3=c*K, v4=v3+A, v5=v4>>31, v6=v4^v5(c2,live-out), v7=v6&M, v8=acc+v7(acc1,live-out), v9=i+1(i1,live-out), v10=v9<KK Known answer: allocation sound + 0 spills; ref==alloc for ALL random inputs; a corrupted allocation (two overlapping vregs aliased to one register) DIVERGES (the verifier catches the miscompile). exit 0.