V.D275 — BAO Angular Scale from τ-Native d_A

BAO angular scale θ_BAO(z) = r_s/d_A(z) from τ-native parameters. At z=0.5: d_A=1302 Mpc, d_A/r_s=8.85. At z=1.0: d_A=1702, d_A/r_s=11.57. Agrees with Planck-ΛCDM to <310 ppm, indistinguishable at DESI DR1 precision.