V.T184 — EHT Shadow T² Correction: f = 1 + ι_τ²/4 at 2.91% over GR

The T² quadrupole correction f=1+ι_τ²/4=1.02912 enlarges the BH shadow by 2.91% over GR Schwarzschild. For M87* (diameter convention): GR gives ~39.7 μas, T² gives ~40.9 μas, vs EHT 42±3 μas. T² prediction is closer to EHT central value. Correction is below current EHT precision (~7%) but detectable by ngEHT at <3% precision.