Correct where= cut 12 cross-product bleeds — meta_purity 0.65→1.0 on our 96-chunk Chroma set

Same author multi-product corpus (96 chunks, products A/B/C + locale/version) on Chroma where=. Compared vector-only vs correct $and vs wrong product. Desk API: $0. pipeline P@5 Recall@5 empty% met