Retro Macintosh: DeepSeek Harness Classic Mac OS 8/9 Skin Plugin

`dsh-retro-mac` is a plugin that recreates the DeepSeek Harness web interface in a Mac OS 8/9 Platinum style. It is fully self-contained, uses inline CSS to ensure zero external resource loading, and provides multiple themes, classic controls, and a Happy Mac boot screen. Users can install it via a command or configuration file, switch between Platinum/Graphite skins and accent colors in settings, and non-intrusively restore the original interface when reverting to the default skin.