Fix Leaflet attribution visibility on desktop

- Position Leaflet bottom-right controls (attribution) away from filter menu
- Set right: 310px on desktop (300px sidebar + 10px spacing)
- Set right: 360px on extra large screens (350px sidebar + 10px spacing)
- Ensures "OpenStreetMap contributors" text is fully visible

Author: claude

css/catchment.css

@@ -187,6 +187,11 @@ body {
         margin-right: 0;
     }
 
+    /* Ensure Leaflet attribution is not hidden by filter menu */
+    .leaflet-bottom.leaflet-right {
+        right: 310px;
+    }
+
     .offcanvas-end {
         visibility: visible !important;
         transform: none !important;
@@ -219,6 +224,11 @@ body {
         margin-right: 350px;
     }
 
+    /* Ensure Leaflet attribution is not hidden by wider filter menu */
+    .leaflet-bottom.leaflet-right {
+        right: 360px;
+    }
+
     .offcanvas-end {
         width: 350px;
     }