The Navier-Stokes Singularity Does Not Exist in Physical Spacetime: A TCC Proof, the SRNUDT Boundary Theorem, and a Critique of the Continuous Spacetime Axiom

We prove, conditional on TCC being the correct Planck-scale description of spacetime, that no cascade-based finite-time singularity occurs in the Navier-Stokes equations in physical spacetime. The turbulent energy cascade is SRNUDT remainder propagation. The Planck floor is the terminal object of C_SRNUDT. The SRNUDT Boundary Theorem (Ploof 2026, Paper A, DOI: 10.5281/zenodo.19326496) establishes that remainder localizes to the compact-K-invariant Planck-floor boundary rather than accumulating at interior points. Cascade-based finite-time blowup requires remainder to concentrate at an interior point approaching zero scale; the Boundary Theorem, applied via the maximal compact subgroup K = SO(3) of SO(3,1), forbids this within TCC spacetime. In cascade-type blowup, vorticity satisfies ||omega(t)||_Linf ~ u_lambda/lambda(t); since lambda(t) >= l_P > 0 for all t in TCC, the Beale-Kato-Majda criterion cannot be satisfied. We further argue that the Clay Millennium Prize formulation presupposes the Continuous Spacetime Axiom (CSA) - a physically unjustified premise at singularity-formation scales - and that the physical and abstract-mathematical NS regularity questions are distinct. The physical question has a clean conditional answer: global regularity holds in TCC spacetime for all cascade-based blowup scenarios. Non-cascade blowup mechanisms (Type I) in TCC spacetime remain an open question.