X72-67: Log-Viscosity Riccati Tangent Scattering Derivative

Continuing from Round 66's fixed-size Jost-Riccati graph and the continuous-parameter extension gap it left (STOP-C70), this round uses t=log ν as the gauge parameter, differentiating the graph G_n exactly to obtain the closed, fixed-size tangent flows H_n and K_n, and proves that the derivative of the normalized central functional f(ν)=a₃(ν)/ν is exactly the "Riccati scattering derivative" Σ(ν)=(∂_t a₃-a₃)/ν²=f'(ν), which weakens the final bridge exactly from "reconstructing the entire singular minimal bundle" to "controlling the crude boundedness of ∫₀^(10⁻⁶)|Σ(s)|ds". Fixed-size tangent numerical diagnostics show the singular scattering coefficients σ₋≈10.137 and σ₊≈-3.436, closely matching Round 60's secant values, with magnitude far below the crude sufficient bound 10⁶. This round does not prove this uniform boundedness; the gap shifts to STOP-C71 (the validated-scattering-derivative/total-variation gap), left for the next round; this round includes numerical verification scripts and CSV data.