fix(deps): update dependency next to v15.5.3

Author: renovate[bot]

site/package-lock.json

@@ -20,7 +20,7 @@
     "clsx": "^2.1.1",
     "js-yaml": "^4.1.0",
     "lucide-react": "^0.536.0",
-    "next": "15.4.5",
+    "next": "15.5.3",
     "react": "19.1.1",
     "react-dom": "19.1.1",
     "react-diff-viewer-continued-react19": "^1.0.0",