IV.T153 — PMNS Large Mixing Requires A-Sector Flavor Rotation Beyond σ-Matrix

σ-polarity matrices for neutrino and charged-lepton sectors share the same eigenvector basis (structural consequence of the [[a,b,0],[b,c,b],[0,b,a]] shape). Therefore V_ℓ†·V_ν ≈ identity and large PMNS mixing requires A-sector (Weak, π-generator) flavor rotation. sin²θ₂₃ ≈ κ_D² = (1−ι_τ)² ≈ 0.434 (PDG 0.45) with A-sector rotation.