Unified Cosmology without Dark Matter: The Reactive Entropic Gravity Framework

We present a unified solution to the current cosmological tensions (H₀ and σ₈) by eliminating the Dark Sector (CDM). We replace the Dark Matter hypothesis with a thermodynamic response function of the vacuum, coupled to the Hubble horizon via a coefficient α ≈ 0.47. We demonstrate via MCMC simulations that this model recovers the 3rd Acoustic Peak of the CMB and the cosmic expansion history with precision indistinguishable from the standard model. Additionally, we identify a metric compression factor Γ ≈ 117 ("TARDIS Effect") necessary to preserve the thermodynamic unitarity of black holes, suggesting an informational origin for gravity.