xby-mermaid-doc: Introduction to the DeepSeek Harness Plugin

xby-mermaid-doc is an online tool in the DeepSeek Harness (DSH) plugin ecosystem, designed to address the issue of developers frequently needing to look up Mermaid syntax when writing technical documentation. The plugin provides two key functions via the MCP protocol: `set_xby_apikey` (setting the API key) and `get_diagram_doc` (retrieving diagram documentation). By obtaining an API key from the official Xiaobenying website, users can call this tool to access various types of diagram documentation, including flowcharts, sequence diagrams, and architecture diagrams. The plugin is MIT-licensed and easy to install, effectively lowering the barrier to writing technical documentation.