X72-45: Visibility-Replicator Dynamics

Picks up Round 44's proof that neither static divdiv geometry nor actual quadratic vorticity realizability can eliminate the first-order transfer between visible and invisible stress (STOP-C48). This round stops the static attack and studies directly the exact dynamics of the visibility ratio η_ω=‖W_L‖_2²/(‖W_L‖_2²+‖W_T‖_2²), splitting it into four terms: stretching selection, Laplacian scale selection, gradient-stress selection, and the conservative Riesz transfer. Proves that a pure sector is stationary at first order but generically receives cross-sector injection at second order — so no universal visibility-evolution direction exists (universal visibility direction is false) — while an exact periodic Beltrami purely-invisible invariant branch also exists; a bounded Piola defect under quartic growth can force η_ω→0. STOP-C49 (Visibility Replicator/Boundary-Injection Compatibility Gap) hands the problem to the next round's analysis of invisible-escape boundary-injection depletion.