Refactor project structure and remove unused modules

- Removed performance monitoring, tools service, and polyfills modules
- Moved formatToolCall helper function to test file
- Simplified imports in index.ts by removing polyfills import
- Cleaned up unnecessary files and consolidated code structure

src/index.ts

@@ -8,7 +8,6 @@
  * @module index
  */
 
-import './polyfills.js';
 import express from 'express';
 import { APP_CONFIG } from './config/app.config.js';
 import { apiRoutes } from './routes/index.js';