Search regional OSINT events

Searches OSINT events across RSS, USGS, GDACS, ACLED, direct News Terminal items, other threat feeds, and Y2 report extractions. Filters by region, country code, bounding box, radius, source, category, severity, time window, or title text. Text search falls back to description substrings. All filters compose with AND, including coordinate and region filters. Events without coordinates remain unless `requireCoordinates=true` or a bounding-box or radius filter is supplied. Supports x402 pay-per-request. Requests with a valid Bearer token use API-key authentication. Without a Bearer API key, start the x402 flow from the `402 Payment Required` response and `PAYMENT-REQUIRED` header; retry with `PAYMENT-SIGNATURE`.