The Interior Observer Cosmological Framework: Paper 30 - One Mass, Zero Fits: Twenty Independent Tests of a Universe Inside a Black Hole

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 — the Interior Observer (IO) framework predicts all major cosmological observables from one measured input (MU = 4. 50 × 10⁵³ kg) and one external constant (γBI = 0. 2375 from Loop Quantum Gravity) with zero continuously fitted parameters. This paper confronts the IO framework's Schur definitive branch (Paper 29: H₀ = 68. 91 km/s/Mpc, Ωₘ = 0. 336, Ωₖ = −0. 006, Ω_Λ = 0. 670) with twenty independent observational tests spanning z = 0 to z = 1100. Results: five direct comparator wins over the Planck ΛCDM fixed-parameter reference, eight non-comparator confirmations, three ties, two indistinguishable, one mild loss, and one pre-registered future prediction — all with zero fitted framework parameters. Key findings include: five independent baryon probes each see the density predicted by the BDP α-ladder; the bare-branch local-clock age (19. 181 Gyr) resolves the Methuselah paradox; and the Sandage-Loeb redshift drift is a falsifiable prediction testable by the ELT ANDES spectrograph. https: //dfife. github. io/index. html v1. 3 (April 2026): Rebuild audit. Schur branch retired (Paper 29): √ (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, Ωₘ = 0. 349, Ωₖ = −0. 046) confirmed as sole survivor. All twenty tests recomputed on active branch. Branch labels updated throughout. BAO readout kernel (Paper 29, Steps 449/451–459) applied. R shift parameter removed (ΛCDM diagnostic, not IO observable). Open/Closed Problems section added. Appendix inherited from Paper 29 v1. 2 (April 2026): Paper 31 consistency update. §1. 3 and §10. 2 updated: Paper 31 confirms CLASS cannot represent the IO three-baryon architecture and removes all CLASS χ² numbers from the published record; the IO-native Boltzmann solver specification is now documented (Paper 31 §15. 18). §10. 5 updated: Paper 31 derives the Weyl-response bridge (ηIO = 0. 623, ΣIO = x^−1/2 = 0. 811), alleviating the S₈ tension within the linear scalar sector and providing the framework’s first structure-growth prediction (S₈ = 0. 793). kSZ σ₈ note annotated. Twenty scorecard tests unaffected — none depend on Aₛ, τ, or the CMB transfer function. v1. 1 (April 2026): Corrected draft. OS dust cycloid scoped to high-z approximation (z > 5) for formation times. Cosmic age corrected from 33. 36 Gyr (dust cycloid, overestimates due to missing Λ) to 19. 181 Gyr (bare-branch mixed-fluid FRW integral, Paper 5). JWST formation times and 46% ratio unaffected. All computations by Codex (OpenAI, o4-mini-high) on the Schur definitive branch (Paper 29). Closed-FRW K=+1 sin (χ) distances throughout