X72-42: Piola–Vorticity Visible Stress

Picks up Round 41's compression of the nonlocal Piola defect into the scalar 𝔙_ω=1/12|ω|²+1/4ℛ_iℛ_j(ω_iω_j) (STOP-C45), identifies it as the Riesz-visible projection of the trace-free vorticity stress W=ω⊗ω-1/3|ω|²I, and establishes the visible/invisible orthogonal decomposition together with the Vorticity-Stress Visibility Pythagorean identity. Proves that under this projection the transport–Riesz commutator only performs a conservative transfer of visible/invisible energy, without creating total quartic stress energy, so total stress growth can only come from vorticity–strain alignment and diffusion; the genuine remaining nonlocal obstruction is whether the double-divergence-free invisible stress itself carries extra compensating regularity. STOP-C46 (Visible–Invisible Vorticity-Stress Transfer/Double-Divergence Compensation Gap) hands this problem to the next round.