build: upgrade Vite to 6.x

Author: mrholek

package.json

@@ -49,6 +49,6 @@
     "postcss": "^8.4.49",
     "prettier": "3.3.3",
     "sass": "^1.81.0",
-    "vite": "^5.4.11"
+    "vite": "^6.0.11"
   }
 }