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>

scripts/install-n8n-node.sh

@@ -0,0 +1,50 @@
+#!/bin/bash
+
+# Script to install the MCP node into n8n
+
+set -e
+
+echo "Installing n8n MCP node..."
+
+# Build the project
+echo "Building project..."
+npm run build
+
+# Create custom nodes directory if it doesn't exist
+N8N_CUSTOM_DIR="${N8N_CUSTOM_DIR:-$HOME/.n8n/custom}"
+mkdir -p "$N8N_CUSTOM_DIR/nodes/n8n-mcp"
+
+# Copy node files
+echo "Copying node files to n8n custom directory..."
+cp dist/n8n/MCPNode.node.js "$N8N_CUSTOM_DIR/nodes/n8n-mcp/"
+cp dist/n8n/MCPApi.credentials.js "$N8N_CUSTOM_DIR/nodes/n8n-mcp/"
+
+# Copy utils for the node to work
+mkdir -p "$N8N_CUSTOM_DIR/nodes/n8n-mcp/utils"
+cp -r dist/utils/* "$N8N_CUSTOM_DIR/nodes/n8n-mcp/utils/"
+
+# Create package.json for the custom node
+cat > "$N8N_CUSTOM_DIR/nodes/n8n-mcp/package.json" << EOF
+{
+  "name": "n8n-nodes-mcp",
+  "version": "1.0.0",
+  "description": "MCP integration for n8n",
+  "n8n": {
+    "n8nNodesApiVersion": 1,
+    "credentials": [
+      "dist/n8n/MCPApi.credentials.js"
+    ],
+    "nodes": [
+      "dist/n8n/MCPNode.node.js"
+    ]
+  },
+  "dependencies": {
+    "@modelcontextprotocol/sdk": "^1.12.1"
+  }
+}
+EOF
+
+echo "MCP node installed successfully!"
+echo "Please restart n8n for the changes to take effect."
+echo ""
+echo "Custom node location: $N8N_CUSTOM_DIR/nodes/n8n-mcp"