dsh-web-plugin-explain: Display description when Web plugin list expands

`dsh-web-plugin-explain` is a DSH Web plugin (MIT License) maintained by community developers, designed to address the difficulty of quickly identifying the source and functionality of plugins as their number grows. By enhancing the "Plugin List" page in Web Settings, this plugin achieves the following core functions: 1. Uniformly display the `description` field from the plugin package's `package.json`, displaying a placeholder when parsing fails without affecting the list's normal rendering; 2. Automatically add a "Third-party" tag to plugins that do not start with `@deepseek-ai/` or `cordis:`, making it easier to distinguish between built-in and external capabilities; 3. Support comprehensive search by plugin ID, module name, description text, and "Third-party" tag. The plugin has been published to npm, and users can access it via...