The Neutral Matching Unit in QDL Closure Grammar: A Uniqueness Theorem for 1/18 from Binary–Ternary Sector Coupling, Z 6 Operator Grading, and Electroweak Residual Preservation

The Quantized Dimensional Ledger (QDL) closure sequence identified a compact recurring grammar across several sectors of known physics, including the objects 1/8, 1, 1/4, 1/18, 49/72, 53/18, 9 + 1/27, and rho_QDL. Among these, the unit 1/18 is the most important unresolved residue because it appears in the scalar residual coefficient, the weak-angle residual coefficient, electromagnetic residual structure, and the cosmological horizon-screening ansatz. This paper formulates a neutral matching uniqueness theorem. Under declared QDL admissibility conditions — binary weak-residual closure, ternary sector exposure, source-target neutral interface matching, minimal positive inverse exposure, Z6-compatible sector…