The Dark Energy 6/7 Factor from Face Laplacian Topology

Derives the cosmological constant suppression factor 6/7 as a Tier 1 theorem from the topology of the face adjacency Laplacian of the truncated octahedron. Two inert modes — A₁g (zero mode, connectivity) and A₂u (maximum mode, bipartiteness of the cube graph Q₃) — are identified via rank-nullity and spectral graph theory respectively. The remaining (F−χ)/F = 12/14 = 6/7 propagating modes set the ratio ρ_Λ/ρ₀. Result: ρ_Λ = 5.849×10⁻²⁷ kg/m³, 0.47% from Planck 2018. Zero free parameters.