fix(deps): update dependency @netlify/sdk to v4

Author: renovate[bot]

package.json

@@ -11,7 +11,7 @@
   },
   "dependencies": {
     "@netlify/functions": "^3.1.10",
-    "@netlify/sdk": "^3.0.0",
+    "@netlify/sdk": "^4.0.0",
     "react": "^19.0.0",
     "react-dom": "^19.0.0"
   },