Update README.md

## Add Zettelkasten MCP Server

This PR adds the Zettelkasten to the community servers list.

### Project Overview
Comprehensive AI-powered knowledge management system that implements the proven Zettelkasten (slip-box) method with modern AI assistance.

### Key Features
- **Atomic Note Management**: Create, organize, and connect atomic ideas
- **AI-Powered Workflows**: CEQRC process for enhanced learning
- **Full-Text Search**: SQLite FTS5 with advanced query syntax
- **Intelligent Linking**: AI-suggested connections between notes
- **Multiple Interfaces**: CLI, REST API, Streamlit UI, and MCP server
- **Comprehensive Documentation**: Setup guides and examples included

### MCP Server Details
- **Transport**: STDIO
- **Tools**: 7 comprehensive tools for note management and AI workflows
- **Dependencies**: OpenAI API (optional, has stub mode)
- **Python**: 3.11+ with modern async/await patterns
- **Setup**: Automated setup script with Claude Desktop config generation

### Repository Information
- **URL**: https://github.com/joshylchen/zettelkasten
- **License**: MIT
- **Documentation**: Complete setup guide in `docs/MCP_SETUP.md`
- **Tests**: Comprehensive test coverage included

This server demonstrates sophisticated MCP patterns and provides real value for knowledge workers and researchers using AI assistants.

README.md

@@ -464,6 +464,7 @@ Official integrations are maintained by companies building production ready MCP
 - <img height="12" width="12" src="https://cdn.zapier.com/zapier/images/favicon.ico" alt="Zapier Logo" /> **[Zapier](https://zapier.com/mcp)** - Connect your AI Agents to 8,000 apps instantly.
 - <img height="12" width="12" src="https://www.zenable.app/zenable_light.svg" alt="Zenable Logo" /> **[Zenable](https://docs.zenable.io/integrations/mcp/getting-started)** - Clean up sloppy AI code and prevent vulnerabilities
 - **[ZenML](https://github.com/zenml-io/mcp-zenml)** - Interact with your MLOps and LLMOps pipelines through your [ZenML](https://www.zenml.io) MCP server
+- **[Zettelkasten](https://github.com/joshylchen/zettelkasten)**- Comprehensive AI-powered knowledge management system implementing the Zettelkasten method. Features atomic note creation, full-text search, AI-powered CEQRC workflows (Capture→Explain→Question→Refine→Connect), intelligent link discovery, and multi-interface access (CLI, API, Web UI, MCP). Perfect for researchers, students, and knowledge workers.
 - <img height="12" width="12" src="https://zizai.work/images/logo.jpg" alt="ZIZAI Logo" /> **[ZIZAI Recruitment](https://github.com/zaiwork/mcp)** - Interact with the next-generation intelligent recruitment platform for employees and employers, powered by [ZIZAI Recruitment](https://zizai.work).
 
 ### 🌎 Community Servers