The Interior Observer Cosmological Framework - Paper 29: The Branch Consistency Audit: Schur Branch Retirement, the Galaxy/Quasar BAO Readout Kernel, and Direct Data Confrontation

Beginning from two premises — (1) the observable universe exists inside a Schwarzschild black hole, and (2) the physics inside the horizon is the same as outside — this paper resolves the assembly gap that has persisted since Paper 20 through a branch self-consistency audit, establishes the unique surviving observational branch, and confronts the IO framework with the most direct expansion-rate measurements available. The carried observational package (H₀ = 67.58, Ω_m = 0.349, Ω_k = −0.006) is shown to be internally inconsistent — a hybrid combining legacy-branch values with Schur-branch curvature. Two self-consistent branches are reconstructed; the Schur definitive branch (H₀ = 68.91, Ω_m = 0.336, Ω_k = −0.006) is the unique surviving prediction. Against 35 cosmic chronometer measurements and 13 DESI DR2 BAO points, the Schur branch (χ² = 42.48) outperforms the Planck ΛCDM fixed-parameter reference (χ² = 44.80) with zero continuously fitted parameters. The BAO Ω_m residual (1.19σ) is within normal statistical scatter. The assembly gap is closed as a bookkeeping error, not missing physics. Multi-AI adversarial collaboration: Claude (Anthropic), Codex/ChatGPT (OpenAI), Gemini (Google DeepMind). Full paper series available at https://zenodo.org/communities/interior-observer/ https://dfife.github.io/index.html v1.2 (April 2026): Rebuild audit. Schur branch retired: √(1+γ²) vacuum ansatz identified as hidden fitted parameter, K_Λ shifted from 49.85 to 48.50. Paper 10 legacy branch (H₀ = 67.58) confirmed as sole survivor. Title, abstract, and conclusion rewritten. All branch-dependent values updated to Paper 10 legacy branch. Data confrontation (§4) recomputed on Paper 10 legacy branch. Scorecard updated: A_s = 2.007 (C1b killed), H₀ = 67.58. Assembly gap closure simplified. Open Problems updated. Appendix replaced with Paper 28 v1.3 clean chain + Paper 29 theorem-grade steps only. Appendices B, C, D removed (not theorem-grade). Author block corrected. Terminology: Schur definitive → conditional Schur, Rosetta → gauge partition. v1.1 (April 2026): Validation corrections applied. BAO Ω_m Jacobian investigation added. Full Appendix A inherited from Paper 28 v1.0 (Steps 1–443) with Paper 29 results appended (Steps 444–460).