add Xero MCP Server to README.

Author: john-zhang-dev

README.md

@@ -305,6 +305,7 @@ A growing set of community-developed and maintained servers demonstrates various
 - **[X (Twitter)](https://github.com/EnesCinr/twitter-mcp)** (by EnesCinr) - Interact with twitter API. Post tweets and search for tweets by query.
 - **[X (Twitter)](https://github.com/vidhupv/x-mcp)** (by vidhupv) - Create, manage and publish X/Twitter posts directly through Claude chat.
 - **[xcodebuild](https://github.com/ShenghaiWang/xcodebuild)**  - 🍎 Build iOS Xcode workspace/project and feed back errors to llm.
+- **[Xero-mcp-server](https://github.com/john-zhang-dev/xero-mcp)** - Enabling clients to interact with Xero system for streamlined accounting, invoicing, and business operations.
 - **[xiyan_mcp_server](https://github.com/XGenerationLab/xiyan_mcp_server)** An MCP server that supports fetching data from a database using natural language queries, powered by XiyanSQL as the text-to-SQL LLM.
 - **[XMind](https://github.com/apeyroux/mcp-xmind)** - Read and search through your XMind directory containing XMind files.
 - **[YouTube](https://github.com/ZubeidHendricks/youtube-mcp-server)** - Comprehensive YouTube API integration for video management, Shorts creation, and analytics.