feat: complete n8n integration with MCP Client Tool support and version badge automation

This major update adds comprehensive n8n integration, enabling n8n-mcp to run
as an MCP server within n8n workflows using the MCP Client Tool node.

## Key Features

### n8n Integration (NEW)
- Full MCP Client Tool compatibility with protocol version negotiation
- Dedicated n8n mode with optimized Docker deployment
- Workflow examples and n8n-friendly tool descriptions
- Quick deployment script for easy setup

### Protocol & Compatibility
- Intelligent protocol version selection (2024-11-05 for n8n, 2025-03-26 for others)
- Fixed schema validation issues with n8n's nested output format
- Enhanced parameter validation with clear error messages
- Comprehensive test suite for protocol negotiation

### Security Enhancements
- Dynamic UID/GID generation (10000-59999) for Docker containers
- Improved error sanitization for production environments
- Fixed information leakage in error responses
- Enhanced permission handling for mounted volumes

### Performance Optimizations
- Docker build time reduced from 13+ minutes to 1-2 minutes
- Image size reduced from ~1.5GB to ~280MB
- Fixed ARM64 build failures
- Optimized to use runtime-only dependencies

### Developer Experience
- Comprehensive parameter validation for all MCP tools
- Made README version badge dynamic from package.json
- Enhanced test coverage with session management tests
- Improved CI/CD with informational patch coverage

### Documentation
- Added comprehensive N8N_DEPLOYMENT.md guide
- Updated CHANGELOG.md for version 2.9.0
- Enhanced CLAUDE.md with n8n-specific instructions
- Added deployment scripts and examples

## Technical Details

Files Added:
- Dockerfile.n8n, docker-compose.n8n.yml for n8n deployment
- Protocol version negotiation utilities
- n8n integration test suite
- Session management tests
- Deployment and test scripts
- Version badge update scripts

Files Modified:
- Enhanced MCP server with n8n mode support
- Improved HTTP server with better error handling
- Updated Docker configurations for security
- Enhanced logging for n8n compatibility
- CHANGELOG.md with comprehensive update description

This update makes n8n-mcp a first-class citizen in the n8n ecosystem,
enabling powerful AI-assisted workflow automation.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

README.md

@@ -2,7 +2,7 @@
 
 [![License: MIT](https://img.shields.io/badge/License-MIT-yellow.svg)](https://opensource.org/licenses/MIT)
 [![GitHub stars](https://img.shields.io/github/stars/czlonkowski/n8n-mcp?style=social)](https://github.com/czlonkowski/n8n-mcp)
-[![Version](https://img.shields.io/badge/version-2.8.3-blue.svg)](https://github.com/czlonkowski/n8n-mcp)
+[![Version](https://img.shields.io/badge/version-2.9.0-blue.svg)](https://github.com/czlonkowski/n8n-mcp)
 [![npm version](https://img.shields.io/npm/v/n8n-mcp.svg)](https://www.npmjs.com/package/n8n-mcp)
 [![codecov](https://codecov.io/gh/czlonkowski/n8n-mcp/graph/badge.svg?token=YOUR_TOKEN)](https://codecov.io/gh/czlonkowski/n8n-mcp)
 [![Tests](https://img.shields.io/badge/tests-1356%20passing-brightgreen.svg)](https://github.com/czlonkowski/n8n-mcp/actions)
@@ -322,6 +322,14 @@ Deploy n8n-MCP to Railway's cloud platform with zero configuration:
 
 **Restart Claude Desktop after updating configuration** - That's it! 🎉
 
+## 🔧 n8n Integration
+
+Want to use n8n-MCP with your n8n instance? Check out our comprehensive [n8n Deployment Guide](./docs/N8N_DEPLOYMENT.md) for:
+- Local testing with the MCP Client Tool node
+- Production deployment with Docker Compose
+- Cloud deployment on Hetzner, AWS, and other providers
+- Troubleshooting and security best practices
+
 ## 💻 Connect your IDE
 
 n8n-MCP works with multiple AI-powered IDEs and tools. Choose your preferred development environment: