chore: migrate from npm to pnpm

package.json

@@ -4,6 +4,7 @@
   "description": "[Claude Status](https://status.claude.com/)'s webhook for Telegram bot. Hosted on Cloudflare Workers",
   "main": "src/index.js",
   "type": "module",
+  "packageManager": "pnpm@11.1.1",
   "scripts": {
     "dev": "wrangler dev",
     "deploy": "wrangler deploy",