Maritime

Provides chokepoint context and optional AIS-related maritime data.

Auth: AISSTREAM_API_KEY enables richer AIS behavior where supported.
Failure modes: missing key, remote stream unavailable, no vessels in a monitored region.
Behavior: static chokepoint context remains available, live source health reports degraded when remote data is unavailable.
Test: run a sweep and inspect maritime markers, source health, and network metrics.