Scalar-Tensor Knot-Web Cosmology: From Degeneracy Surface to Topological Selection

Version 3. Major upgrade: the Majorana mass open problem is promoted from Open to Conjecture with proved kinematic skeleton. Summary table: 8 established links (7 proved, 1 conjecture) and 2 open problems. Builds on: No-Go Theorem (DOI: 10. 5281/zenodo. 18866200) and CS Boundary Completion (DOI: 10. 5281/zenodo. 18894178). Changelog: v2: Volumetric Traversal Theorem (R ~ t^2/3 from CS action scaling), Friedmann recovery (ρ ~ R^-3 from mass conservation), dimension-dependent prediction R (t) ~ t^ (d-1) /3 uniquely selecting d=3. v3: Spin-wall defect mechanism for Majorana mass. Longitudinal spin defect O_ (0, 1) on boundary torus T² opens odd theta-channel (Lemma 7. 2: ϑ₂ → ϑ₁) with leading |sin (Φ/2) | factor (Proposition 7. 3). Dilute transfer-matrix exponentiation yields |m_ββ| = m₀|sin (Φ/2) | (Conjecture 7. 4), conditional on dynamical input εflip (σK, t). Three consistency checks verified (Proposition 7. 5).