chore: migrate repository to pnpm

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-opencode)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

package.json

@@ -20,8 +20,9 @@
     "vitest.config.ts"
   ],
   "type": "module",
+  "packageManager": "pnpm@10.32.1",
   "engines": {
-    "node": ">=20"
+    "node": ">=20.19.0"
   },
   "scripts": {
     "dev": "tsx src/index.ts",
@@ -43,10 +44,10 @@
     "@types/node": "^24.0.0",
     "tsx": "^4.20.0",
     "typescript": "^5.8.0",
-    "vitest": "^3.2.0"
+    "vitest": "^4.0.0"
   },
   "dependencies": {
     "@modelcontextprotocol/sdk": "^1.27.1",
-    "zod": "^3.25.76"
+    "zod": "^4.1.11"
   }
 }