IV.D364 — Pentagon Dark Coupling: κ_D Exponent 5/4 = |gen|/(2·|lobes|)

Pentagon dark coupling: the exponent 5/4 in η̄ = ι_τ^(-1/4)·κ_D^(5/4)/√5 derives from |generators|/(2·|lobes|) = 5/4. Each of the 5 generators {α,π,γ,η,ω} contributes one quarter-revolution of dark coupling κ_D^(1/4). Total: κ_D^(5·1/4). Factor 1/√5 = |gen|^(-1/2) is L² normalization over 5 coherent generators.