Chip-G0202/dsh-deepseek-search-account

DeepSeek account-backed web search and page fetching for DeepSeek Harness sessions whose chat model runs through a third-party subscription or gateway (for example OpenCode Go): registers deepseek-account-search and deepseek-account-fetch providers that call the official Search and Fetch APIs with the signed-in DeepSeek account token, so the built-in web_search and web_fetch keep working without a DEEPSEEK_API_KEY.