CDN-238: The First Audit — Contract compliance check and taxonomy application for the GCFT dual register

CDN-238 audits the CDN-237 five-rule contract for the GCFT dark sector dual register. Three rules pass (C1: residual always explicit; C3: κ-proxy is a fit; C4: overshoot capped), one is partial (C2: taxonomy complete but no real residuals classified), and one is deferred (C5: branch verdict awaits data). The saturation rule is formalised as A_eff = min(A_raw, A⁰(1+ε_sat)) with ε_sat=0.02 default. The {P,F,S,E} taxonomy is applied to five archetype clusters. Neither branch dominates; CDN-239 inherits the first data-facing gate.