dsh-ui-zoom: Browser-Style Zoom for DeepSeek Harness and DSH Desktop

`dsh-ui-zoom` is a plugin that provides browser-style UI zooming for DeepSeek Harness and DSH Desktop. It supports zoom adjustments from 50% to 200% via keyboard shortcuts (Ctrl +/-, mouse wheel) or the bottom-right widget, with settings persistently saved by source. Implemented using CSS zoom, the plugin does not affect fixed panel rendering and supports Chinese, English, and Russian. An installation command is included, aiming to improve interface readability at high resolutions.