feat: Implement score increment on click and cleanup CSS

- Implemented score increment functionality directly on the score display in GameDetail.jsx.

- Deleted obsolete ValidationModal.module.css to finalize style consolidation.

- This resolves all outstanding tasks for the refactor and adds a minor feature enhancement.

- Closes #1

src/components/GameDetail.jsx

@@ -28,7 +28,14 @@ const GameDetail = ({ game, onFinishGame, onUpdateScore, onBack }) => {
             key={name + idx}
           >
             <span className={styles['player-name']}>{name}</span>
-            <span className={styles['score']} id={`score${idx+1}`}>{scores[idx]}</span>
+            <span
+              className={styles['score']}
+              id={`score${idx + 1}`}
+              onClick={() => !isCompleted && onUpdateScore(idx + 1, 1)}
+              aria-label={`Aktueller Punktestand für ${name}: ${scores[idx]}. Klicken zum Erhöhen.`}
+            >
+              {scores[idx]}
+            </span>
             <button
               className={styles['score-button']}
               disabled={isCompleted}

src/components/ValidationModal.module.css

@@ -1 +0,0 @@
-/* DEPRECATED: All modal styles are now in Modal.module.css */