style(pet): soften pet sprite drop-shadow blur

Bump blur from 1.5px to 3px so the right-side sprite shadow reads as a
diffuse glow instead of a hard offset. Opacity stays at 0.18.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

Author: ChanceYu

src/styles.css

@@ -2462,7 +2462,7 @@ select {
   transform-origin: center;
   transition: none;
   image-rendering: pixelated;
-  filter: drop-shadow(4px 0 1.5px hsl(var(--foreground) / 0.18));
+  filter: drop-shadow(4px 0 3px hsl(var(--foreground) / 0.18));
 }
 
 .pet-sprite {