Fix: Wrap ternary else-branch in Fragment for SelectedImage

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

studio-v2/app/learn/[unitId]/match/page.tsx

@@ -172,6 +172,7 @@ export default function MatchPage() {
           </div>
         </div>
       ) : (
+        <>
         <div className="grid grid-cols-2 gap-4">
           {/* Left: English */}
           <div className="space-y-2">
@@ -212,6 +213,7 @@ export default function MatchPage() {
 
         {/* Image preview for selected word */}
         <SelectedImage items={roundItems} selectedId={selectedLeft} isDark={isDark} />
+        </>
       )}
     </ExerciseLayout>
   )