Summarize LiveTrack sessions and prune stale ones

Fetching a session's track now also grabs its summary (name, activity
type, distance, duration) from the same page and stores it — sessions
the panel has actually shown replace their raw UUID with that summary,
and are kept indefinitely regardless of age. A session nobody ever
opened (no summary) is more likely test/dead data than something worth
keeping, so it's dropped automatically after 48h.

app.rb

@@ -254,11 +254,13 @@ module Maptool
       halt 404, json(error: "session has no token") if session["token"].to_s.empty?
 
       begin
-        points = LiveTrackClient.track_points(session["id"], session["token"])
+        result = LiveTrackClient.fetch(session["id"], session["token"])
       rescue LiveTrackClient::FetchError => e
         halt 502, json(error: "could not fetch track: #{e.message}")
       end
+      LIVETRACK_STORE.set_summary(session["id"], LiveTrackClient.summarize(result))
 
+      points = result.points
       coordinates = points.filter_map { |p| p.dig("position", "lon") && p.dig("position", "lat") && [p["position"]["lon"], p["position"]["lat"]] }
       halt 502, json(error: "track has no positions") if coordinates.empty?
       last = points.last