fix: implement Single-Session architecture to resolve MCP stream errors

- Add ConsoleManager to prevent console output interference with StreamableHTTPServerTransport
- Implement SingleSessionHTTPServer with persistent session reuse
- Create N8NMCPEngine for clean service integration
- Add automatic session expiry after 30 minutes of inactivity
- Update logger to be HTTP-aware during active requests
- Maintain backward compatibility with existing deployments

This fixes the "stream is not readable" error by implementing the Hybrid
Single-Session architecture as documented in MCP_ERROR_FIX_PLAN.md

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

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

package.json

@@ -1,6 +1,6 @@
 {
   "name": "n8n-mcp",
-  "version": "2.3.0",
+  "version": "2.3.1",
   "description": "Integration between n8n workflow automation and Model Context Protocol (MCP)",
   "main": "dist/index.js",
   "scripts": {
@@ -11,9 +11,11 @@
     "test-nodes": "node dist/scripts/test-nodes.js",
     "start": "node dist/mcp/index.js",
     "start:http": "MCP_MODE=http node dist/mcp/index.js",
+    "start:http:legacy": "MCP_MODE=http node dist/http-server.js",
     "http": "npm run build && npm run start:http",
     "dev": "npm run build && npm run rebuild && npm run validate",
     "dev:http": "MCP_MODE=http nodemon --watch src --ext ts --exec 'npm run build && npm run start:http'",
+    "test:single-session": "./scripts/test-single-session.sh",
     "test": "jest",
     "lint": "tsc --noEmit",
     "typecheck": "tsc --noEmit",