Inner Horizon Stability, Mass Inflation Damping, and Information Preservation in the CCEGA Framework

Regular black hole solutions in the Curvature-Controlled Extra-Dimensional Gravity and Emergent Unification (CCEGA) framework possess a two-horizon structure: an outer (Hawking) horizon at r₂ ≈ 2 GM/c² and an inner (Cauchy) horizon at r₁ ≈ 0.26 GM/c². The inner horizon carries a negative surface gravity κ₁ ≈ −3.47 c³/GM, which in standard general relativity would drive the mass inflation instability with growth timescale τ ∼ 0.29 GM/c³. We show that the CCEGA modulus field φ provides a damping mechanism: at the inner horizon φ(r₁) ≈ 0.77, reducing the effective gravitational coupling to G_eff(r₁) ≈ 0.23G and suppressing the effective surface gravity to κ₁ᵉᶠᶠ ≈ −0.82 c³/GM — a factor of 4 reduction. We derive the stability map in the (r_c, M) parameter space and identify the extremal limit r_c ≲ 0.15 GM/c² below which the inner horizon disappears entirely. For astrophysical black holes with r_c ∼ ℓ_Pl, full stability is recovered. The regular core imposes Dirichlet boundary condition u(0) = 0 for all multipoles ℓ ≥ 0, ensuring perfect reflection and unitarity of the scattering matrix. These results extend the CCEGA programme to the quantum information sector without modifying the observational predictions for the Einstein Telescope.