Geometric Reaction: Reactive Cosmology

In the fiducial nu-RFE/RLM regime, Gamma_R produces a percent-level growth imprint, yielding an approximately 0.6 percent suppression in fσ8 at z ≃ 1 relative to matched LambdaCDM anchors. Simultaneously, a modest early-residue shift of the acoustic ruler (for example, Δr_s ≃ −0.3 Mpc, within the CMB-safe budget), combined with a small late-time tempo drift, raises the CMB-honest global value to H0_cos ≃ 70–71 km s⁻¹ Mpc⁻¹. We derive a local linear “geometric ceiling”: under the conservative ruler constraint |Δr_s| ≲ 0.6 Mpc, purely late-time deformations cannot support H0_cos ≳ 71 without incurring a strong CMB likelihood penalty. We interpret this not as a failure, but as a container diagnostic. The local distance ladder can correspond to an effective low-z container G_local with H0_local ≃ 73, which need not coincide with the global FRW-like container G_cos.Different containers can unfold at different tempos. Agreement is possible, but not required.