III.D18 — Coupling Ledger

The No Knobs Ledger: systematic inventory of all inter-sector couplings. 10 entries (4 self-couplings + 6 cross-couplings). Each entry κ(S_i, S_j) = f_{ij}(ι_τ, M_d) is a specific rational function of ι_τ evaluated at a specific primorial depth.