Map: highlight pin when navigated from packet detail

Red circle marker with tooltip at the target coordinates,
fades out after 10 seconds. Makes it obvious where the
packet location is on the map.

public/index.html

@@ -86,7 +86,7 @@
   <script src="app.js?v=1774126708"></script>
   <script src="home.js?v=1774042199"></script>
   <script src="packets.js?v=1774219409"></script>
-  <script src="map.js?v=1774219409" onerror="console.error('Failed to load:', this.src)"></script>
+  <script src="map.js?v=1774219621" onerror="console.error('Failed to load:', this.src)"></script>
   <script src="channels.js?v=1774331200" onerror="console.error('Failed to load:', this.src)"></script>
   <script src="nodes.js?v=1774218049" onerror="console.error('Failed to load:', this.src)"></script>
   <script src="traces.js?v=1774135052" onerror="console.error('Failed to load:', this.src)"></script>

public/map.js

@@ -139,6 +139,16 @@
     }
     map = L.map('leaflet-map', { zoomControl: true }).setView(initCenter, initZoom);
 
+    // Drop a highlight pin if navigated from a packet detail link
+    if (urlParams.get('lat') && urlParams.get('lon')) {
+      const pinLat = parseFloat(urlParams.get('lat'));
+      const pinLon = parseFloat(urlParams.get('lon'));
+      const pin = L.circleMarker([pinLat, pinLon], { radius: 12, color: '#ef4444', fillColor: '#ef4444', fillOpacity: 0.3, weight: 2 }).addTo(map);
+      pin.bindTooltip(`${pinLat.toFixed(4)}, ${pinLon.toFixed(4)}`, { permanent: true, direction: 'top', offset: [0, -10] });
+      // Fade out pin after 10 seconds
+      setTimeout(() => { map.removeLayer(pin); }, 10000);
+    }
+
     const isDark = document.documentElement.getAttribute('data-theme') === 'dark' ||
       (document.documentElement.getAttribute('data-theme') !== 'light' && window.matchMedia('(prefers-color-scheme: dark)').matches);
     const tileLayer = L.tileLayer(isDark ? TILE_DARK : TILE_LIGHT, {