dsh-keyless-search: Keyless Multi-Engine Search Provider for DeepSeek Harness

`dsh-keyless-search` is a third-party plugin for DeepSeek Harness (DSH), designed to replace the native `web_search` tool. It uses a local Chrome browser to perform real web search without an API key and without consuming model turns, with intelligent features such as automatic proxy detection, concurrent multi-engine searches, language awareness, and automatic browser instance reclamation. The plugin supports command-based installation and configuration in DSH environments, making it suitable for high-frequency keyless search scenarios, though it has cold-start latency and a limit on the number of results.