Baryon Asymmetry from First Principles: A Parameter-Free Derivation of ηB

We derive the baryon-to-photon ratio ηB = 6. 15×10⁻¹⁰ from a single master equation with zero free parameters. The result agrees with Planck 2018 observations (6. 12×10⁻¹⁰) to 0. 49%. Four falsifiable predictions are provided.