dsh-desktop-packager: Packaging DeepSeek Harness as a macOS Desktop App

The dsh-desktop-packager plugin is designed to address the cumbersome process of deploying DeepSeek Harness (DSH) as a standalone desktop application (.app/.dmg). The tool supports customized configuration through four tabs in the Settings interface of dsh web, including design scheme, plugin/model selection, and permission settings (with passwords encrypted using scrypt). After installation, users need to run the `dsh_package_desktop` command to package the built DSH into a macOS application. This solution uses a dual-end architecture and implements runtime filtering through configuration file injection, making it suitable for scenarios requiring the distribution of specific configurations or private deployment. Note that it must be run in a macOS environment and requires Node.js ≥ 22.