feat(card-sorting): add smooth transition to drop shadow

Add smooth 0.2s ease transition to box-shadow that applies both when
picking up and dropping cards:

- Remove conditional transition (was 'none' while dragging)
- Always apply 'box-shadow 0.2s ease' transition
- Shadow now smoothly animates in when starting drag
- Shadow smoothly animates out when dropping card

Previously the shadow appeared instantly when clicking because the
transition was disabled during drag. Now it smoothly fades in/out
for a more polished feel.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

apps/web/src/arcade-games/card-sorting/components/PlayingPhaseDrag.tsx

@@ -325,7 +325,7 @@ function AnimatedCard({
         cursor: isSpectating ? 'default' : 'grab',
         touchAction: 'none',
         userSelect: 'none',
-        transition: isDragging ? 'none' : 'box-shadow 0.2s ease',
+        transition: 'box-shadow 0.2s ease',
         borderRadius: '12px',
         overflow: 'hidden',
       })}