The Relativistic Dynamic Universe (RDU) framework proposes a mechanical origin for dark energy, replacing the static cosmological constant with a dynamic Chronos Field potential. This model treats vacuum energy as governed by a modified alpha-attractor potential with fixed steepness parameter α = 1.100 and base energy density V0,DE ≈ 2.48 × 10−47 GeV4. Applying slow-roll formalism yields equation-of-state parameters w0 ≈ −0.998 and wa ≈ +0.013, consistent with recent DESI, Planck, and Pantheon+ observational contours. The physical mechanism involves Lepto-Aumons (superluminal vacuum excitations) undergoing Aumonic Bremsstrahlung, leading to a deterministic energy leakage from the dark energy field. Redshift is reinterpreted as Lattice Fatigue in the Chronos Field lattice rather than geometric expansion, offering a resolution to the Hubble tension through vacuum substrate mechanics.