dsh-theme-liquid-glass: Liquid Glass theme for DSH Web UI

`dsh-theme-liquid-glass` is an MIT-licensed theme plugin for the DSH Web UI, version 0.3.1, requiring Node >= 18. Aiming to unify the customization of the Web UI appearance through a Liquid Glass style, the plugin covers elements such as background wallpapers, input cards, message bubbles, buttons, and model selectors. Its core capabilities include real-time adjustment of glass parameters via CSS variables, support for SVG edge refraction effects, and the provision of multi-format (URL, local image/video/HTML) wallpaper management and custom animation demos. Users can adjust parameters like background blur and brightness in real-time via the settings panel, and it supports one-click disabling or resetting to the default state. Installation requires only executing `dsh plugin --profile web add`.