feat: route tiles use OpenStreetMap standard raster for denser place/street labels

frontend/src/components/ui/RouteTileMap.jsx

@@ -2,11 +2,8 @@ import { useEffect, useRef } from 'react'
 import L from 'leaflet'
 import { sportColor } from '../../utils/format'
 
-// Voyager raster tiles — same street style used on the activity map. We split
-// the basemap (no labels) from a labels-only overlay so place names can be drawn
-// *above* the route line instead of being hidden underneath it.
-const BASE_URL = 'https://{s}.basemaps.cartocdn.com/rastertiles/voyager_nolabels/{z}/{x}/{y}{r}.png'
-const LABELS_URL = 'https://{s}.basemaps.cartocdn.com/rastertiles/voyager_only_labels/{z}/{x}/{y}{r}.png'
+// OpenStreetMap standard raster — denser street/place labels than Carto Voyager.
+const TILE_URL = 'https://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png'
 
 function decodePolyline(encoded) {
   if (!encoded) return []
@@ -41,12 +38,7 @@ export default function RouteTileMap({ polyline, sportType, className = '' }) {
       zoomSnap: 0,
     })
     mapRef.current = map
-    L.tileLayer(BASE_URL, { maxZoom: 19 }).addTo(map)
-    // A dedicated high-z pane keeps the labels overlay on top of the route line.
-    map.createPane('labels')
-    map.getPane('labels').style.zIndex = 650
-    map.getPane('labels').style.pointerEvents = 'none'
-    L.tileLayer(LABELS_URL, { maxZoom: 19, pane: 'labels' }).addTo(map)
+    L.tileLayer(TILE_URL, { maxZoom: 19, subdomains: 'abc' }).addTo(map)
     return () => { map.remove(); mapRef.current = null }
   }, [])