This is part I https://zenodo.org/records/16978450  
This is Part III [https://zenodo.org/records/16978002]

This is part IV https://zenodo.org/records/16978234  

This paper develops a unified theoretical framework showing that the cosmic microwave background (CMB) emerges as Hawking radiation from cosmological horizons in an information-saturated universe. By combining the Einstein–Hilbert action, quantum field theory in curved spacetime, and the island paradigm of quantum extremal surfaces, the model amplifies the Gibbons–Hawking temperature (2.269 × 10⁻³⁰ K) into the observed CMB temperature (2.725 K) through exponential enhancement governed by the saturation index C = 0.91. The framework demonstrates that cosmological horizons behave like black hole horizons undergoing Page-curve evolution, with the Lambert W function regulating quantum divergences. It resolves the cosmological constant problem through a Λ split: 78% geometric contribution and 22% informational contribution. Observable consequences include negative redshift drift at z = 1, small CMB low-ℓ anomalies consistent with Planck, and the natural emergence of ultralight dark matter from hidden horizon information. The model unifies black hole thermodynamics, quantum information theory, and observational cosmology, offering falsifiable predictions testable with JWST, ELT, Euclid, and CMB-S4.