Render a session's track on the map

Clicking a LiveTrack session now fetches and draws its track (line +
latest position). Garmin's own API 403s any plain server-side request
(Cloudflare bot protection), so LiveTrackClient fetches the session
page instead and pulls the track out of the server-rendered data
embedded in it. The webhook now captures the session's token too,
since the id alone isn't enough to fetch anything.

public/css/style.css

@@ -440,12 +440,35 @@ html, body {
 }
 
 .livetrack-panel__item {
+  border-bottom: 1px solid #f0f0f0;
+}
+
+.livetrack-panel__row {
   display: flex;
   align-items: center;
   justify-content: space-between;
   gap: 8px;
-  padding: 6px 0;
-  border-bottom: 1px solid #f0f0f0;
+  width: 100%;
+  padding: 6px 4px;
+  border: none;
+  border-radius: 4px;
+  background: none;
+  font: inherit;
+  text-align: left;
+  cursor: pointer;
+}
+
+.livetrack-panel__row:hover {
+  background: #f0f0f0;
+}
+
+.livetrack-panel__row.active {
+  background: #f1e6fb;
+}
+
+.livetrack-panel__row.loading {
+  opacity: 0.6;
+  cursor: wait;
 }
 
 .livetrack-panel__id {