BETAIL-BOYS/TradeFlow-Core

AI Summary: This issue proposes to externalize the Express server's hardcoded port into an environment variable, loaded via `dotenv`. This change will enable easier configuration for different deployment environments. It involves installing `dotenv`, creating a `.env.example` file, and updating the server's startup script to read `process.env.PORT`.

AI Summary: This issue proposes integrating Helmet.js into the Express application to enhance security by adding essential HTTP headers. The current system lacks basic security headers, and adding Helmet is described as a quick, standard, and painless solution for Node.js applications.