feat(flights): show the tracked aircraft's Planespotters photo in Contacts

Tracking a civil flight asks Planespotters for that aircraft's photo, once
per aircraft, straight from the browser. The CONTEXT panel's CONTACTS view
shows it under the flight's name with the photographer's credit, as a plain
link to the photo's page. Only images on plnspttrs.net and pages on
www.planespotters.net are ever shown or linked. Military aircraft and a
converted TR-3B are never looked up.

Flight lookups (type, route, photo) whose source failed temporarily are
asked again after a 60-second cool-down; 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.

Browser QA scripts that track a flight answer the photo lookup themselves,
so they never call the third party.

docs/CURRENT-STATE.md

@@ -2812,6 +2812,17 @@ in `ais-store.js`. Common response caps, request coalescing and query parsing
 have their own modules. `server/providers/local.js` composes these with the
 remaining providers and retains existing named compatibility exports.
 
+The tracked flight also gets a photo. The browser asks Planespotters for it
+directly (`src/sources/live/standalone.js`, read by
+`src/data/planespottersPhoto.js`), once per aircraft, and the CONTEXT panel's
+CONTACTS view shows it under the flight's name with the photographer's credit
+and a link to the photo's page. Military aircraft and a converted TR-3B are
+never looked up. A flight lookup (type, route or photo) whose source failed
+temporarily is asked again after a 60-second cool-down while the aircraft
+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`.
+
 `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