IV.R412 — OQ η̄ Exponents: SOLVED (τ-effective) after Sprint 7F

OQ η̄ exponents SOLVED at τ-effective scope. All three factors in η̄ = ι_τ^(-1/4)·κ_D^(5/4)/√5 structurally derived from |lobes|=2 and |generators|=5: quarter-lobe holonomy (-1/4), pentagon dark coupling (5/4), generator L² normalization (1/√5). No free parameters. Resolves open question from Sprint 6B (IV.P200 exponent mystery). Remaining: NNLO correction to improve -2285 ppm precision.