Implement n8n-MCP integration

This commit adds a complete integration between n8n workflow automation and the Model Context Protocol (MCP):

Features:
- MCP server that exposes n8n workflows as tools, resources, and prompts
- Custom n8n node for connecting to MCP servers from workflows
- Bidirectional bridge for data format conversion
- Token-based authentication and credential management
- Comprehensive error handling and logging
- Full test coverage for core components

Infrastructure:
- TypeScript/Node.js project setup with proper build configuration
- Docker support with multi-stage builds
- Development and production docker-compose configurations
- Installation script for n8n custom node deployment

Documentation:
- Detailed README with usage examples and API reference
- Environment configuration templates
- Troubleshooting guide

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

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

src/index.ts

@@ -0,0 +1,45 @@
+import dotenv from 'dotenv';
+import { N8NMCPServer } from './mcp/server';
+import { MCPServerConfig, N8NConfig } from './types';
+import { logger } from './utils/logger';
+
+// Load environment variables
+dotenv.config();
+
+async function main() {
+  const config: MCPServerConfig = {
+    port: parseInt(process.env.MCP_SERVER_PORT || '3000', 10),
+    host: process.env.MCP_SERVER_HOST || 'localhost',
+    authToken: process.env.MCP_AUTH_TOKEN,
+  };
+
+  const n8nConfig: N8NConfig = {
+    apiUrl: process.env.N8N_API_URL || 'http://localhost:5678',
+    apiKey: process.env.N8N_API_KEY || '',
+  };
+
+  const server = new N8NMCPServer(config, n8nConfig);
+  
+  try {
+    await server.start();
+  } catch (error) {
+    logger.error('Failed to start MCP server:', error);
+    process.exit(1);
+  }
+}
+
+// Handle graceful shutdown
+process.on('SIGINT', () => {
+  logger.info('Received SIGINT, shutting down MCP server...');
+  process.exit(0);
+});
+
+process.on('SIGTERM', () => {
+  logger.info('Received SIGTERM, shutting down MCP server...');
+  process.exit(0);
+});
+
+main().catch((error) => {
+  logger.error('Unhandled error:', error);
+  process.exit(1);
+});