Use custom marker.png for Leaflet map markers

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

assets/modules/event-map.js

@@ -40,7 +40,14 @@ function geocodeAndRender(address, mapEl) {
                 subdomains: 'abcd',
             }).addTo(map)
 
-            L.marker([lat, lon]).addTo(map).bindPopup('<b>' + address + '</b>').openPopup()
+            const icon = L.icon({
+                iconUrl: '/marker.png',
+                iconSize: [40, 40],
+                iconAnchor: [20, 40],
+                popupAnchor: [0, -40],
+            })
+
+            L.marker([lat, lon], { icon }).addTo(map).bindPopup('<b>' + address + '</b>').openPopup()
         })
         .catch(() => {
             mapEl.innerHTML = '<div style="display:flex;align-items:center;justify-content:center;height:100%;background:#f3f4f6;"><p style="font-weight:700;color:#9ca3af;">Carte indisponible</p></div>'