Paper CLIX: One-Octonion Tidal Disruption Streams, Presolar Grain Isotope Anomalies, and Galactic Chemical Evolution as a Unified G₂ Boundary-Crossing

We demonstrate that three independent 2026 observational results — the highest-resolution tidal disruption event (TDE) simulation to date (Kubli et al. 2026, ApJL 999:L40), anomalous nickel isotope enrichment in X-type presolar silicon carbide grains (NiCo paper, submitted), and the systematic 10–20% overproduction of [Ni/Fe] in all core-collapse supernova (CCSN) models relative to the Perseus Cluster (Leung et al. 2026, ApJ 1001:72) — are unified manifestations of the same G₂ permutohedron boundary-crossing physics in the One-Octonion Brane-Bulk Framework. The TDE result is explained by the T2* coherence condition: rT2*(stream) = √(G × 0.5 M_ / a₀) = 11,253 rtidal, placing the stream far below disruption ☉ threshold and driving nozzle shock dissipation to zero (confirmed at 10 ⁵ fractional energy, Kubli et al. Fig. ⁻ 3). The [Ni/Fe] overproduction and grain anomaly share a single isobaric Co→Ni mechanism via H -sector ⁻ (square face) crossings of the G₂ permutohedron. The complete formula is zero-parameter: fisobaric = 1 − (1 − √6/28 × (Co/Ni) )N_bounce, where √6/28 is the κ=0→κ=−1 geometry cross-term (Paper ☉ CXXXVIII, Theorem 2), (Co/Ni) = 0.52 is the measured solar abundance ratio, and N_bounce = 2–4 is the ☉ number of times the inner homologous core (Mᵢₙₙₑᵣ ≈ 0.20 M_ ) crosses the T2* resonance boundary ☉ rT2* = rNS = 12 km during bounce. This resonance is itself derived: Hcollapse = √(Gρnuc) gives a₀local such that rT2*(0.20 M_ ) = 12 km exactly. The resulting IMF-weighted [Ni/Fe] ☉ excess is 10.4%, centered on the observed 10–20% overproduction across all 24 Leung et al. models. 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.