X72-37: Pressure-Response Defect Energy

Picks up Round 36's proof that cofactor–pressure replenishment coherence has no universal dephasing, and that affine strain can achieve a perfect response H_p^0=-C_S^0 (STOP-C40). This round defines the affine-response defect E_p=H_p^0+C_S^0, and derives its exact PDE and the (moving-domain) defect-energy budget. Proves that the local strain coupling in the defect equation is not coercive: the pure-strain self-forcing and the explicit determinant source cancel exactly in defect coordinates, and the genuine remaining forcing consists of three terms — vorticity, gradient terms, and the transport–Riesz commutator. Critical control comes down to S∈L_t²L_x³; STOP-C41 (Affine-Response Defect/Critical Commutator–Gradient Gap) hands the remaining nonlocal forcing to the next round's analysis of transport–Riesz commutator depletion.