DCRP66 / X72R49: Cofactor Null-Channel Repair and Two-Stress Correlation

Building on DCRP65's claim that all three of X72 Round38's null channels are now closed, this round points out that the claim needs correction: X72 Round38's own pressure self-commutator null identity shows that the defect factor actually entering the triple increment commutator is the strain cofactor δC_S⁰, not δE_p alone — so the δE_p increment budget DCRP64 proved does not rule out the cofactor itself being spatially constant. This round uses the cofactor's proper norm identity |C|²=|S|⁴/6 to prove, under the aligned branch and isotropic covariance, that a spatially constant cofactor is likewise impossible, completing this overlooked null-channel repair. Since the pressure source is exactly the difference between the cofactor and the actual vorticity-stress amplitude, the true triple-correlation frontier is thereby reduced precisely to a single 4:1 correlation-balance condition, Q_Cω=4Q_CC, which is handed to DCRP67 to address its spectral geometry.