Add in-app WeChat scanning via Tencent iLink API:
- server.js: QR code PNG renderer, WeChat API proxy, plugin auto-install
- index.html: WeChat channel card with QR display and polling UI
- Windows-Start.bat: auto-install WeChat plugin on startup
- Windows-Install.bat: copy WeChat plugin during installation
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>