CDN-263: The SPARC Test — GCFT Computational Discovery Note

Tests GCFT's dSph-calibrated interpolation function ν(x) = 1 + κ(x·a₀) against the SPARC Radial Acceleration Relation (2630 points, 14 bins, 153 galaxies) and Baryonic Tully-Fisher Relation (175 galaxies). Result: ν_GCFT fails the RAR with weighted RMS 0.144 dex (MOND simple: 0.019 dex). Transition-zone underprediction of +0.165 dex across 7 bins. Cluster-scale floor κ_cl = 0.152 absent in galaxy Newtonian regime. CDN-264 pre-registered for direct RAR refit.