Add run_webhook tool for executing workflows via webhooks

This commit adds a new MCP tool, run_webhook, which allows executing n8n workflows via webhooks instead of using the API directly. This implementation:

1. Creates a new RunWebhookHandler class that:
   - Takes a workflowName parameter and automatically prepends "webhook/" to create the full path
   - Uses basic authentication from environment variables
   - Makes HTTP requests to the webhook endpoints and returns the responses

2. Adds new environment variables:
   - N8N_WEBHOOK_USERNAME: Username for webhook basic authentication
   - N8N_WEBHOOK_PASSWORD: Password for webhook basic authentication

3. Updates server configuration and handlers to register and expose the new tool

4. Adds comprehensive documentation in:
   - execution-tools.md with examples and schema
   - README.md with configuration and usage information

This provides a simpler alternative to the API-based workflow execution, allowing Claude to trigger n8n webhooks directly.

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

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

src/tools/execution/handler.ts

@@ -11,7 +11,8 @@ import { N8nApiError, getErrorMessage } from '../../errors/index.js';
 import { 
   ListExecutionsHandler, 
   GetExecutionHandler,
-  DeleteExecutionHandler
+  DeleteExecutionHandler,
+  RunWebhookHandler
 } from './index.js';
 
 /**
@@ -37,6 +38,9 @@ export default async function executionHandler(
       case 'delete_execution':
         return await new DeleteExecutionHandler().execute(args);
         
+      case 'run_webhook':
+        return await new RunWebhookHandler().execute(args);
+        
       default:
         throw new McpError(
           ErrorCode.NotImplemented,