Show Live/Ended status on LiveTrack sessions

A session's own end timestamp is absent until the activity is
actually stopped, so its presence/absence is the status signal — no
new data needed, just reading what was already there. Shown as a
badge next to the session in the list and in its map hover popup.

public/css/style.css

@@ -446,8 +446,7 @@ html, body {
 .livetrack-panel__row {
   display: flex;
   align-items: center;
-  justify-content: space-between;
-  gap: 8px;
+  gap: 6px;
   width: 100%;
   padding: 6px 4px;
   border: none;
@@ -472,6 +471,8 @@ html, body {
 }
 
 .livetrack-panel__label {
+  flex: 1;
+  min-width: 0;
   overflow: hidden;
   text-overflow: ellipsis;
   white-space: nowrap;
@@ -481,6 +482,23 @@ html, body {
   font-family: monospace;
 }
 
+.livetrack-badge {
+  flex-shrink: 0;
+  padding: 2px 6px;
+  border-radius: 3px;
+  background: #e5e5e5;
+  color: #666;
+  font-size: 10px;
+  font-weight: 600;
+  text-transform: uppercase;
+  letter-spacing: 0.02em;
+}
+
+.livetrack-badge--live {
+  background: #d7f3e3;
+  color: #1b7a43;
+}
+
 .livetrack-panel__time {
   flex-shrink: 0;
   color: #888;