fix(client-entry): füge CSS-Fallback für Production-Build hinzu

src/server/routes/client-entry.tsx

@@ -25,6 +25,7 @@ export function clientEntry(c: Context<BlankEnv>) {
       console.warn('Could not read Vite manifest, using fallback:', error);
       // Fallback to a generic path
       jsFile = "/assets/index-Ccx6A0bN.js";
+      cssFiles = ["/assets/index-RdX4PbOO.css"];
     }
   }