Part III - Derivation of Mass Spectrum in the SRD Cubic Cell–Tokamak Hierarchy

n Part I, space was modeled as a cubic cell lattice, and "spatial response" was redefined as the source of physical quantities by functionally separating the ε channel (Face: storage/diffusion) and the μ channel (Column: reciprocation/focusing/rotational inertia). In Part II, the sequential transition of ε→μ, phase accumulation, multi-standing-wave ensembles, Zitterbewegung (ZBW) equivalent circular motion, g≈2 structure, charge sign separation (Δr), and the reproduction of the new Coulomb law at the η→1 boundary were connected as a single continuous process. This Part III continues this flow to calculate "particle mass" based on: (i) the saturation matching of the 137-layer natural Tokamak (α⁻¹), (ii) the 224 constant derived from the complete cubic tensor response (16) and phase contacts (14), (iii) the average slip 8/(3π) induced by rotational dynamics, and (iv) the 3D volume resonance 6π⁵. Specifically, the mass ratios of the second generation (Muon) and third generation (Tau) are quantitatively derived relative to the **electron mass (m_e)**. Furthermore, the "geometric impossibility of the 4th generation" is proven through 137-layer saturation, exhaustion of the 224 modes, and 3D axial closure.