feat(vessels): a selected vessel shows its Open Vessel Photos photo and MMSI

Selecting a vessel asks Open Vessel Photos (a free, keyless API) for its
photo by MMSI, once per MMSI. The CONTACTS view shows it under the vessel's
name and MMSI with the photographer, the photo's open licence and a link to
the vessel's page; only images on Open Vessel Photos' own host are shown, and
an answer about another MMSI is no photo. The vessel source exposes the lookup
as getEnrichment({kind: 'photo'}) and fetchOpenVesselPhoto for applications
with their own vessel source.

docs/CURRENT-STATE.md

@@ -3199,6 +3199,15 @@ stays in view or tracked; an answer, found or not, and a permanent refusal
 stay final for the session. A route belongs to the callsign it was looked up
 for, so a callsign change drops the old route. See `DATA_SOURCES.md`.
 
+A selected vessel gets a photo the same way. The browser asks Open Vessel
+Photos for it by MMSI (`fetchOpenVesselPhoto` in
+`src/sources/live/standalone.js`, read by `src/data/openVesselPhoto.js`), once
+per MMSI (`src/layers/vessels/photos.js`), and the CONTACTS view shows it under
+the vessel's name and MMSI ("NAME · MMSI 366999709") with the photographer,
+the photo's open licence and a link to the vessel's page. A vessel without an
+MMSI is never looked up; a miss stays final for the session, and a failed
+lookup is asked again after five minutes.
+
 `gods-eye-view/server/providers/live` is a Node-only entry for the existing
 plugins and shared request helpers. Importing it starts no sockets or timers.
 The existing aircraft normalizer is separately available through the portable