DSH Plugin Description Extension: Adding Chinese and English descriptions to the Web plugin list

`dsh-plugin-description` is a composite plugin for DeepSeek Harness (DSH), designed to provide bilingual (Chinese and English) functional descriptions for the plugin list page in Web Settings. The plugin includes a built-in description dictionary covering 134 modules in the DSH out-of-the-box bundle, supporting the display, search, and editing of descriptions on plugin cards. It exposes the `pluginDescriptions` service and the `GET /plugin-descriptions` data endpoint, allowing Host-side plugins within the same process to register or override custom descriptions. Users can edit descriptions directly on the page and persist them to `<DSH_HOME>/plugin-descriptions.json`, ensuring that custom content is not lost after upgrades or reinstallation. The description priority is: