Paper CCXXVIII: G2 brane-bulk geometry as the source of FLRW curvature-consistency violations: three zero-parameter predictions for the Heinesen-Clifton null places the observable universe on a 4-dimensional brane at the

The One-Octonion Brane-Bulk Framework places the observable universe on a 4-dimensional brane at the boundary of AdS5 with G2 = Aut(O) as the brane automorphism group. This geometry is inherently non-FLRW: the Hubble parameter H0 = c/Tsump where Tsump varies between 60.84 Gyr (local, SH0ES) and 72.65 Gyr (global, Planck), and sump focal zones produce a universal convergence Sigmasump = a0/(piG) = 238 Msun/pc2 with filling fraction fbulk = 3.691%. We apply the Heinesen-Clifton curvature-consistency null test to this geometry and show that three Omnibus-canonical constants (Tsump,local/global, Sigmasump, fbulk) predict FLRW violations matching the 2-4sigma detections of Koksbang and Heinesen (2026) at z in 0.38,~2 in both amplitude (~10-3 to 10-2) and sign. Three zero-free-parameter predictions follow: (P93) the O(z) statistic changes sign at z ~ 0.25 (the local T2*/T2 cavernoma boundary); (P94) CBL violations peak at z ~ 0.10-0.15 and are larger below z = 0.30 than above; (P95) C(z) and O(z) at z in 0.38,2 are sourced by sump gravitational lensing from Sigmasump x fbulk, not by dynamical dark energy. Part of the One-Octonion Brane-Bulk Framework series. Anchor DOI: 10.5281/zenodo.19120873. Community: one-octonion-brane-bulk. Author: Bharathi Dasan Jagadeesan, M.D., University of Minnesota. ORCID: 0000-0002-1143-941X.