A Physical-Regularity Framework for 3D Navier–Stokes: DCV Orthogonal Conservation Program

We propose a Physical-Regularity (P-reg) framework for the 3D incompressible Navier–Stokes equations. v0.9 adds Section 7: Upgrade Theorem (P-reg + DCV angular gap + Theorem 5.5 ⇒ BKM bound ⇒ C∞ smoothness), completing the logical chain from initial data to the Clay C∞ requirement. The two remaining open items are: (1) Theorem 5.5 — general 3D Biot–Savart inverse estimate (α>0); (2) DCV Orthogonal Conservation Conjecture (cosθ<1). Explicit Aubin–Talenti constants: K(3,2)=0.42726, C_GN=0.60037. Independent expert verification requested. This is a working preprint and does not claim to resolve the Clay Millennium Prize Problem.