RIP-U and the ω = 0 Obstruction in Davies Dynamics: Upper Envelopes, Witness Floors, and Falsification Protocols for Separation-Dependent Decoherence Rates

We isolate the dynamic hinge in typed separation-to-rate-to-power pipelines within the Davies (weak-coupling, Markovian) setting in finite dimension. First, we formulate an upper-envelope statement (RIP-U): under an explicit factorized bath-correlation envelope with separation-dependent amplitude f(epsilon) and integrable time profile, Fourier-transformed Davies rates inherit an O(f(epsilon)) envelope. Under additional regularity assumptions preventing trivial degeneracies, this yields a worst-case bound kappa_up(epsilon) <= C f(epsilon) for the instantaneous relative loss rate of a coherence-like functional. Second, we isolate a structural obstruction to lower-envelope statements: we prove an exact identity for the omega = 0 contribution to the Davies Dirichlet form, E^(0)sigma(O) = (gamma(0)/2) ||[S(0),O]||^2{2,sigma}, and derive a witness mechanism showing how omega = 0 channels can enforce a non-vanishing dissipation contribution for suitable observable families. We emphasize directionality: RIP-U (upper) does not imply a positive lower envelope kappa_down(epsilon) without additional family-qualified input. All assumptions are explicit and accompanied by falsification routes. v2 (no v1 number is changed): two v1 assumptions are upgraded to proved statements in their canonical instances -- Delta-MONO holds unconditionally for the energy pinching (Davies covariance plus data processing), and a sufficient bridge with an explicit constant is proved; the cross-reference labels are repaired (in v1 every assumption and theorem was typeset as "Definition x.y"); Table 1 is re-typeset (overlapping text in v1); the omega = 0 identity is placed within the corrected Bohr-channel decomposition of the companion 2601.0023 (it is exactly the omega = 0 sector, and the plain-commutator form provably fails at omega != 0); and a verification suite reproduces every proved item numerically, including the identity at machine precision and an explicit family with kappa_down much smaller than kappa_up under the same envelope.