Auto-incident watchdog: DBSCAN + Bayesian corroboration draft generator

New watchdog at scripts/auto-incident-watchdog.py cross-runs the DBSCAN unsupervised anomaly model with the Bayesian corroboration model every 6 hours. When DBSCAN flips a country-day AND the Bayesian posterior is at least 0.5 AND no incident exists for that country within +/-7 days AND there is at least one confirmed-source evidence row (OONI / CensoredPlanet / Voidly probes — IODA disruption rows are excluded), it writes a DRAFT JSON to /opt/voidly-ai/data/auto_incidents_queue/ for editorial review. Drafts are exposed at GET /v1/atlas/auto-incidents-pending and are NEVER counted in the public 343-citable-censorship headline. The watchdog never writes to the incidents table — promotion is manual. First run: 0 drafts (the 4 DBSCAN flips today all failed the corroboration gate). Honest caveat: false-positive rate is uncontrolled.