fix: switchMapStyle loads style as JSON with absolute tile URLs

Fixes trails/tracks not rendering after theme switch.
The issue was that map.setStyle(url) caused MapLibre to resolve
relative tile paths without /enduro/ prefix, resulting in 404s.

src/web/app.js

@@ -88,6 +88,7 @@ function switchMapStyle() {
   if (!map) return;
   const dark = isDarkTheme();
   const basePath = window.location.pathname.replace(/\/[^/]*$/, '') || '';
+  const tileBase = window.location.origin + basePath;
   const styleUrl = dark ? basePath + '/style-dark.json' : basePath + '/style.json';
 
   // Save current position before style change
@@ -96,19 +97,22 @@ function switchMapStyle() {
   const bearing = map.getBearing();
   const pitch = map.getPitch();
 
-  fetch(styleUrl, { method: 'HEAD' }).then(r => {
-    if (r.ok) {
-      map.setStyle(styleUrl);
-      // Restore position and overlays after style loads
-      map.once('idle', () => {
-        map.jumpTo({ center, zoom, bearing, pitch });
-        rebuildMapOverlays();
-      });
-    } else {
-      console.log('Map style not available:', styleUrl);
+  fetch(styleUrl).then(r => {
+    if (r.ok) return r.json();
+    throw new Error('Style not available');
+  }).then(style => {
+    // Fix tile URLs to absolute (same as initMap)
+    if (style.sources && style.sources['trails-tiles'] && style.sources['trails-tiles'].tiles) {
+      style.sources['trails-tiles'].tiles = [`${tileBase}/api/tiles/{z}/{x}/{y}.mvt`];
     }
+    map.setStyle(style);
+    // Restore position and overlays after style loads
+    map.once('idle', () => {
+      map.jumpTo({ center, zoom, bearing, pitch });
+      rebuildMapOverlays();
+    });
   }).catch(() => {
-    // Network error, don't switch
+    // Network error or style not available, don't switch
   });
 }
 
@@ -1436,52 +1440,9 @@ async function initMap() {
     zoomEl.textContent = 'z' + zoom;
   }
 
-  // ─── Scale bar & Zoom level ───────────────────────────────────────────────
-
-  function updateScaleBar() {
-    const zoom = map.getZoom();
-    const lat = map.getCenter().lat;
-    // Метров на пиксель при текущем зуме и широте
-    const metersPerPixel = 156543.03392 * Math.cos(lat * Math.PI / 180) / Math.pow(2, zoom);
-    // Целевая ширина линейки ~100px
-    const targetWidth = 100;
-    const meters = metersPerPixel * targetWidth;
-
-    let label, width;
-    if (meters >= 1000) {
-      const km = Math.round(meters / 1000);
-      label = km + ' км';
-      width = km * 1000 / metersPerPixel;
-    } else {
-      const m = Math.round(meters / 50) * 50 || 50;
-      label = m + ' м';
-      width = m / metersPerPixel;
-    }
-
-    const scaleLine = document.getElementById('scale-line');
-    const scaleLabel = document.getElementById('scale-label');
-    if (scaleLine) scaleLine.style.width = Math.round(width) + 'px';
-    if (scaleLabel) scaleLabel.textContent = label;
-  }
-
-  function updateZoomLevel() {
-    const el = document.getElementById('zoom-level');
-    if (el) el.textContent = Math.round(map.getZoom());
-  }
-
   updateScaleZoom();
-  updateScaleBar();
-  updateZoomLevel();
-  map.on('zoom', () => {
-    updateScaleZoom();
-    updateScaleBar();
-    updateZoomLevel();
-    if (typeof updateHillshadeAvailability === 'function') updateHillshadeAvailability();
-  });
-  map.on('move', () => {
-    updateScaleZoom();
-    updateScaleBar();
-  });
+  map.on('zoom', updateScaleZoom);
+  map.on('move', updateScaleZoom);
 
   map.on('load', () => {
     checkDataAvailability();