Analytical Closure of the Guerrero Backreaction Framework: Räsänen-Wiltshire Formalism and the Roadmap to Λ=0

This paper provides the final analytical bridge for the Guerrero Effective Field Theory (EFT) series, establishing a complete term-by-term budget for the effective cosmological constant (Λ_eff). Building on the kinematic results of Paper 5 (doi:10.5281/zenodo.20085167), this work quantifies the remaining geometric contributions to cosmic acceleration. Key Results:1. Wiltshire Effect Analysis: Quantitative proof that gravitational time dilation in Guerrero solitons (m22=8, Φ/c² ~ 10⁻⁷) is seven orders of magnitude below the threshold required for the clock-rate timescape effect, rendering it negligible (Ω_clock < 10⁻¹²).2. Linear Curvature Limit: Analytical derivation showing that averaged spatial Ricci curvature ⟨R⟩_D vanishes in linear perturbation theory due to exact void-halo symmetry, designating Λ_eff as a purely non-linear phenomenon.3. The Buchert Budget: A complete decomposition where kinematic backreaction (Q) accounts for 20.6% of acceleration, while the remaining 79.4% is formally attributed to non-linear curvature ⟨R⟩_D. This work defines the precise roadmap for Paper 6 (Numerical), specifying the GR N-body simulation parameters (si-FDM with g_NL = 0.0060) required to demonstrate that Λ=0 is a geometric consequence of the Guerrero Rigidity Filter.