IV.P195 — No Axion Required: Strong CP Solved Structurally by SA-i

SA-i is the τ-native Peccei-Quinn mechanism, resolving strong CP without any new field. Structural correspondence: PQ U(1) ↔ ℤ/3ℤ winding symmetry; axion ↔ η-winding integer; f_PQ ↔ κ(C;3)·m_n ≈ 57 MeV (structurally fixed). Testable prediction: ADMX/CASPEr should find null result.