dsh-qr-share: DSH Sidebar QR Code Sharing Plugin

The `dsh-qr-share` plugin of DeepSeek Harness (DSH) aims to solve the problem of synchronizing desktop authentication sessions to mobile devices in web environments. It offers a QR code entry point at the bottom of the sidebar, enabling mobile phones to scan the QR code and reuse the desktop `?token=…` exchange flow for same-session login. The plugin requires Node.js 20 and DSH >= 0.1.0-rc.8, and is released under the MIT open source license. After installation, it must be enabled in the configuration, with route protection used to ensure security.