This preprint presents the Octonionic Cosmological Rotation Hypothesis (OCRH), a theoretical framework that derives Standard Model parameters from the algebraic structure of octonions and their automorphism group G₂. Using heat kernel methods on coset spaces, we obtain the fine-structure constant (1/α = 137.035999083, matching experiment to 0.05σ), the Weinberg angle, strong coupling, and cosmological densities—all with zero free parameters beyond the Planck mass. The framework makes falsifiable predictions for dark energy evolution testable by DESI in 2025-2026.