Csurf

How express-check-csurf-middleware-usage happens in JavaScript/Express and how to fix it

A high-severity CSRF vulnerability was identified in `tower_game/index.js` where the Express application lacked any Cross-Site Request Forgery protection middleware. Without CSRF validation, an attacker could craft malicious pages that trick authenticated users into submitting unwanted requests to the game server. The fix adds `csurf` middleware with cookie-based token storage in just four lines of code.