fix: auto-center viewport when puzzle level loads

Call handleCenterView after level load with a short delay to let
the DOM settle, so modules are centered on screen on both mobile
and desktop.

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

src/game/PuzzleView.jsx

@@ -59,7 +59,10 @@ export default function PuzzleView({ level, levelIndex, worldLevels, onBack, onN
 
   useEffect(() => {
     loadLevel();
+    // Center view on modules after level loads and DOM settles
+    const timer = setTimeout(() => handleCenterView(), 100);
     return () => {
+      clearTimeout(timer);
       stopAudio();
       stopTarget();
     };