IV.T205 — α Precision Barrier at 9.8 ppm

α = (121/225)ι_τ⁴ at 9.8 ppm is current precision limit. 11/15 is unique a/b≤100 within 10 ppm of CODATA. All NLO candidates overshoot or wrong sign. Residual likely encodes running coupling effects at ~10⁻⁵ level.