The 17-Dimensional Substrate Theory: Fine-Structure Constant, Electron Shell Capacities, and MOND Scale

We present a 17-dimensional Randers-Finsler configuration space as a rigid geometric substrate. From the local 30-channel comparison algebra of the 5-dimensional effective core we derive the fine structure constant α−¹cl = 208π²/15 ≈ 136. 8585; a finite observer capacity dressing series recovers the CODATA value 137. 036 within 9. 3×10−8. The17D embedding yields a transverse shape stiffness Kₛhape = 13/15 and a chiral active fraction 3/17, which projects to the macroscopic MOND acceleration scale a₀ = 3/17 cH₀. Topological winding sectors around nuclear defects provide a structural motivation for the electron shell capacities (2, 8, 8, 18, 18, 32) ; the precise representation-theoretic derivation remains an open problem addressed in a forthcoming supplement. The framework contains no free parameters and is falsifiable.