Replace target sum with binary

Replaced the target sum with the binary representation once the game is won.

src/components/BinaryNumberGame.tsx

@@ -135,7 +135,7 @@ const BinaryNumberGame = () => {
           <CardContent className="p-6 text-center">
             <h3 className="text-lg font-semibold text-muted-foreground mb-2">Target Sum</h3>
             <div className="text-4xl font-bold text-primary">
-              {hasGameStarted ? targetNumber : "🎯"}
+              {!hasGameStarted ? "🎯" : isGameWon ? targetNumber.toString(2) : targetNumber}
             </div>
           </CardContent>
         </Card>