Modern cosmology faces two severe challenges: the 10 120 discrepancy of the cos- mological constant [1] and the 5σ Hubble tension between early- and late-universe measurements [2]. We demonstrate that both phenomena emerge naturally and inextricably from the same geometric phase transition within a discrete K = 12 Face-Centered Cubic (FCC) vacuum lattice [4]. Recent simulations of the Selection- Stitch Model (SSM) confirm the internal bulk sheets of this lattice are exactly flat (σz <10−10L for 25 of 27 substantial layers, with inter-layer spacing matching the ideal FCC value 2/3a to 0.04%), meaning the bulk carries zero bending stress (Λbulk = 0) [5]. Consequently, dark energy is strictly a holographic boundary ef- fect. Modeling this expanding boundary as an elastic thin plate, we derive a bare geometric tension of ΩΛ,bare ≈0.623. Concurrently, we show that non-linear struc- ture formation in the late universe creates macroscopic cosmic voids, fracturing the continuous lattice and exposing the bare vacuum [4]. This local symmetry breaking triggers a topological phase transition, shifting the active nucleation channels of the unit cell from a shielded state (νearly = 12) to an exposed state (νlate = 13) [4]. This single void-induced 13/12 topological boost natively amplifies the 67.4 km/s/Mpc CMB baseline to exactly 73.02 km/s/Mpc, resolving the Hubble tension [4]. Apply- ing this identical 13/12 holistic volumetric correction to the bare boundary tension yields an effective dark energy density of ΩΛ ≈0.675 [4], natively aligning with Planck data without continuous free parameters [3].