Fix: Radio search results empty + texture quality

- Search API: read title/subtitle/url from _source.page (nested)
- Channel click: extract correct ID from URL (last segment)
- Replace earth texture with higher-res 4096x2048 original

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

server/src/plugins/radio/api.ts

@@ -77,13 +77,16 @@ export async function fetchPlaceChannels(placeId: string): Promise<RadioChannel[
 /** Sender/Orte/Länder suchen */
 export async function searchStations(query: string): Promise<SearchHit[]> {
   const data = await apiFetch(`/search?q=${encodeURIComponent(query)}`);
-  return (data?.hits?.hits ?? []).map((h: any) => ({
-    id: h._id ?? '',
-    type: h._source?.type ?? 'unknown',
-    title: h._source?.title ?? '',
-    subtitle: h._source?.subtitle ?? '',
-    url: h._source?.url ?? '',
-  }));
+  return (data?.hits?.hits ?? []).map((h: any) => {
+    const page = h._source?.page ?? {};
+    return {
+      id: page.map ?? h._id ?? '',
+      type: h._source?.type ?? 'unknown',
+      title: page.title ?? '',
+      subtitle: page.subtitle ?? '',
+      url: page.url ?? '',
+    };
+  });
 }
 
 /** Stream-URL auflösen (302 Redirect → tatsächliche Icecast/Shoutcast URL) */