dsh-web-search-ark: Volcengine Ark Web Search Provider for DeepSeek Harness

The `dsh-web-search-ark` plugin for DeepSeek Harness (DSH) is designed to address search authentication failures and web search requirements for DeepSeek on the Volcengine Ark platform. It registers the `ark-official` provider, calls the Ark Responses API, and maps the returned search results to the DSH format. Users must install a specific version of DSH, configure pnpm, place the plugin files, and set the `VOLCENGINE_API_KEY`. The plugin supports configuring parameters in Settings, charges based on actual search requests, has no caching mechanism, and strictly follows directory requirements to ensure proper dependency resolution.