dsh-wallpaper-engine: Integrate Downloaded Wallpapers from Wallpaper Engine into DeepSeek Harness Web Background

`dsh-wallpaper-engine` is a MIT-licensed DeepSeek Harness (DSH) web plugin designed to integrate locally downloaded image or video wallpapers from Wallpaper Engine into the DSH interface as backgrounds. Maintained by sakuraaa667, the plugin supports automatic discovery of wallpapers from Steam Workshop and local projects, offering thumbnail browsing, search, one-click application, and real-time refresh on the settings page. It enables video looping with muted playback and high-resolution image adaptation, provides panel and background brightness adjustments to optimize readability, and persists wallpaper selection states, automatically restoring them after restart. Installation requires a Node.js >=22 environment, is added via the `dsh plugin` command, and can be configured through a configuration file.