Rename "Neues Spiel" button text to "New Game"

Updated the button label in the TopBar component to display "New Game" instead of "Neues Spiel." This change aligns the interface language with English for consistency.

frontend/src/components/TopBar.jsx

@@ -90,7 +90,7 @@ export default function TopBar({
 
         {/* Neues Spiel Button */}
         <button onClick={newGame} style={styles.primaryBtn}>
-          ✦ Neues Spiel
+          ✦ New Game
         </button>
       </div>
     </div>