xby-quick-chart: Quick Chart Generator

`xby-quick-chart` is a Model Context Protocol (MCP)-based server plugin designed to simplify the process of calling the Quick Chart API to create charts in DeepSeek Harness (DSH). Users must first register on the Xiao Benyang official website to obtain an API key and set it in the chat interface using the `set_xby_apikey` command. After that, by using the `GetChartImgLink` function and following the Quick Chart parameter specification, they can generate a chart and retrieve its link. The plugin also supports automatic persistent storage of the API key, reducing the barrier to using chart generation.