GCFT-0427: Threshold RGE Execution Baseline — Running the Frozen Weinberg-Angle Ledger Without Private Knobs

A baseline execution of the frozen electroweak threshold specification established in GCFT-0426. This paper evaluates multiple threshold-aware Standard Model baseline scenarios under a strict no-retuning discipline to determine whether the original GCFT electroweak boundary conditions can reproduce the observed Weinberg angle. The analysis shows that threshold placement alone cannot resolve the discrepancy: all tested baselines either encounter a hypercharge pole or evolve in the wrong direction. The remaining blocker is identified as the absence of a GCFT Xi-dependent state vector, beta functions, and electroweak matching equations required for a complete derivation.