v157: THE FIRST FREE NARROWING. rolemark's 150 U-markers save EXACTLY ZERO tokens (unanimously, all 150, one identified cause) while carrying 36.3% of the transform's sigil ambiguity - 13.3x more ambiguous per substitution than the A-marker that holds 100% of the value. Refines v149 rather than contradicting it: the U-marker is not a trade because it has no gain to trade. Scope audit now complete for all four stack members. 1259 tests, 33/33 mutations fire
