fix: add bin property to package.json for yao-pkg

yao-pkg requires a "bin" property to know which file to package
as the entry point. Added bin: "dist/index.js" to fix the packaging
error.

Tested locally - successfully builds 78MB Windows executable.

Author: GhostTypes

package.json

@@ -3,6 +3,7 @@
   "version": "1.0.0",
   "description": "Standalone WebUI for FlashForge 3D Printers",
   "main": "dist/index.js",
+  "bin": "dist/index.js",
   "type": "commonjs",
   "scripts": {
     "dev": "npm run build && concurrently --names \"BACKEND,WEBUI,SERVER\" \"npm run build:backend:watch\" \"npm run build:webui:watch\" \"npm run start:dev\"",