dsh-unitverse: DSH Unit Conversion Plugin

The DeepSeek Harness (DSH) plugin `dsh-unitverse` is specifically designed for data processing and scientific computing agents, providing robust unit conversion capabilities. It covers more than 80 units across 10 major categories, supports Chinese, English, and symbol-based input with case-insensitive matching, and features zero runtime dependencies along with a pure front-end implementation. Once installed, DSH models can perform conversions using the `convert` tool, with results retaining approximately 10 significant digits by default. The plugin also provides an interactive Web view whose language follows the DSH settings. It supports category browsing, one-click swapping of source and target units, switching between temperature and temperature difference, and history backfilling, meeting developers' conversion needs in both command-line and Web environments.