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>

Dockerfile

@@ -0,0 +1,45 @@
+# Build stage
+FROM node:18-alpine AS builder
+
+WORKDIR /app
+
+# Copy package files
+COPY package*.json ./
+
+# Install dependencies
+RUN npm ci
+
+# Copy source code
+COPY . .
+
+# Build the project
+RUN npm run build
+
+# Production stage
+FROM node:18-alpine
+
+WORKDIR /app
+
+# Copy package files
+COPY package*.json ./
+
+# Install production dependencies only
+RUN npm ci --only=production
+
+# Copy built files from builder stage
+COPY --from=builder /app/dist ./dist
+
+# Create a non-root user
+RUN addgroup -g 1001 -S nodejs && adduser -S nodejs -u 1001
+
+# Change ownership
+RUN chown -R nodejs:nodejs /app
+
+# Switch to non-root user
+USER nodejs
+
+# Expose the MCP server port (if using HTTP transport)
+EXPOSE 3000
+
+# Start the MCP server
+CMD ["node", "dist/index.js"]