dsh-zoom: DeepSeek Harness UI Zoom Plugin

The dsh-zoom plugin adds global UI scaling to DeepSeek Harness, addressing the limitation that only body-content scaling is supported by default. It supports `Cmd/Ctrl` shortcuts and script API calls, and persists the selected zoom level. The plugin covers sidebars, menus, and overlays, although Canvas-rendered content may appear blurry at high zoom levels, and shortcuts may not work in certain areas. It is maintained by community developers and can be installed via the command line or in-app.