feat: integrate n8n management tools from n8n-manager-for-ai-agents (v2.6.0)

- Added 14 n8n management tools for workflow CRUD and execution management
- Integrated n8n API client with full error handling and validation
- Added conditional tool registration (only when N8N_API_URL configured)
- Complete workflow lifecycle: discover → build → validate → deploy → execute
- Updated documentation and added integration tests
- Maintains backward compatibility - existing functionality unchanged

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

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

src/config/n8n-api.ts

@@ -0,0 +1,56 @@
+import { z } from 'zod';
+import dotenv from 'dotenv';
+import { logger } from '../utils/logger';
+
+// Load environment variables
+dotenv.config();
+
+// n8n API configuration schema
+const n8nApiConfigSchema = z.object({
+  N8N_API_URL: z.string().url().optional(),
+  N8N_API_KEY: z.string().min(1).optional(),
+  N8N_API_TIMEOUT: z.coerce.number().positive().default(30000),
+  N8N_API_MAX_RETRIES: z.coerce.number().positive().default(3),
+});
+
+// Parse and validate n8n API configuration
+export function loadN8nApiConfig() {
+  const result = n8nApiConfigSchema.safeParse(process.env);
+  
+  if (!result.success) {
+    logger.warn('n8n API configuration validation failed:', result.error.format());
+    return null;
+  }
+  
+  const config = result.data;
+  
+  // Check if both URL and API key are provided
+  if (!config.N8N_API_URL || !config.N8N_API_KEY) {
+    logger.info('n8n API not configured. Management tools will be disabled.');
+    return null;
+  }
+  
+  logger.info('n8n API configured successfully', {
+    url: config.N8N_API_URL,
+    timeout: config.N8N_API_TIMEOUT,
+    maxRetries: config.N8N_API_MAX_RETRIES,
+  });
+  
+  return {
+    baseUrl: config.N8N_API_URL,
+    apiKey: config.N8N_API_KEY,
+    timeout: config.N8N_API_TIMEOUT,
+    maxRetries: config.N8N_API_MAX_RETRIES,
+  };
+}
+
+// Export the configuration (null if not configured)
+export const n8nApiConfig = loadN8nApiConfig();
+
+// Helper to check if n8n API is configured
+export function isN8nApiConfigured(): boolean {
+  return n8nApiConfig !== null;
+}
+
+// Type export
+export type N8nApiConfig = NonNullable<ReturnType<typeof loadN8nApiConfig>>;