improve readme

Author: ihrpr

README.md

@@ -311,6 +311,10 @@ const app = express();
 app.use(express.json());
 
 app.post('/mcp', async (req: Request, res: Response) => {
+  // In stateless mode, create a new instance of transport and server for each request
+  // to ensure complete isolation. A single instance would cause request ID collisions
+  // when multiple clients connect concurrently.
+  
   try {
     const server = getServer(); 
     const transport: StreamableHTTPServerTransport = new StreamableHTTPServerTransport({