CenDTect-style DBSCAN unsupervised anomaly: AUC 0.6506, promoted as second-opinion signal

Adapted the CenDTect approach (Aceto & Pescape 2025 — DBSCAN over OONI feature vectors) to Voidly's 80K-row evidence table. Per-country rolling 45-day window, DBSCAN(eps=75th-pct kNN, min_samples=3) on 12 standardized features. AUC vs v3.3 labeled incidents: 0.6506, just above the 0.65 promote floor. Promoted as a SECOND-OPINION signal — the supervised classifier still wins at 0.99, but DBSCAN surfaces shape-anomalous days the labels never saw. Live at /v1/anomaly/dbscan/{cc}.