chore(deps): update dependency zod to v4

Author: renovate[bot]

package.json

@@ -102,7 +102,7 @@
     "unist-util-stringify-position": "^4.0.0",
     "unist-util-visit": "^5.0.0",
     "ws": "^8.18.3",
-    "zod": "^3.25.76",
+    "zod": "^4.1.5",
     "zod-to-json-schema": "^3.24.6"
   },
   "peerDependencies": {