Force Unification from the Minimal Discrete Épure_[6/6]

We establish six theorems (T1–T6) and two closed results (P1, P2) deriving the three Standard Model gauge couplings from the minimal discrete épure G■ = (ℤ², d■), where d■(P,Q) = |Δx| + 2|Δy| is the unique Minkowski metric on ℤ² minimising the discrete π-invariant π■ = 1. The algebraic invariants c₂(G■) = √5/π and ξ₂(G■) = 37/1296 (T1–T3) encode all coupling information. The causal vertex Θ■ = arctan(2) is the angular horizon of G■, whose derivative jump Δ = √5/2 = 2c₃(G■) encodes the 3D unfolding coefficient (T4). Four simultaneous unfoldings of G■ into four-dimensional spacetime produce total anisotropy α_G■ = 4Θ■ − π (T6). Cartan diagonality implies √rank displacement scaling (T5). The Flux Theorem (P1) is proved exactly via the Fundamental Theorem of Calculus. The stable mode v₂ is characterised by a self-consistent fixed-point equation (P2) with unique solution c* = 1/α_w(G■) = 29.600. Predictions with zero free parameters: 1/α_EM = 137.036043 (error 3×10⁻⁵%), 1/α_w = 29.600 (error <10⁻⁴%), 1/α_s = 8.477 (error 0.077%). SU(5) is geometrically excluded.