Update label from "Account" to "User" in TopBar

The label on the user menu button was changed to improve readability and consistency with the UI language. This ensures better comprehension for users interacting with the application.

frontend/src/components/TopBar.jsx

@@ -46,7 +46,7 @@ export default function TopBar({
             title="User Menü"
           >
             <span style={{ fontSize: 16 }}>👤</span>
-            <span>Account</span>
+            <span>User</span>
             <span style={{ opacity: 0.7 }}>▾</span>
           </button>