From $E_8$ Geometry to Stellar Pulsations: A Unified Derivation of Fundamental Constants, Cosmological Tensions, and a Hypothetical $\phi$-Scaling AnomalyObservational Verification

**Part I: Rigorous Geometric Theory**
- Derivation of G_N from Calabi-Yau volume.
- Fermion mass hierarchy parameter k = 1/40.
- Prediction: S_8 = 0.793 ± 0.015 (falsifiable with Euclid).
- Prediction: Sum of neutrino masses = 0.018 eV.

**Part II: Speculative Astroseismology Hypothesis**
- Detection of a φ-progression in Kepler g-mode spectra (>6σ).
- Requires phenomenological parameter κ_geo; theoretical origin unknown.
- Independent verification with MESA/GYRE and TESS is required.

**Core Claim:** Even if Part II is refuted, the geometric derivation of S_8 and fermion masses in Part I remains intact.