Fix shop room preview showing solid green LCD background.

Include lib/ in Tailwind content so parallax room gradient classes from room-backgrounds.ts are emitted in production CSS.

components/pet/parallax-room-background.tsx

@@ -47,7 +47,10 @@ export function ParallaxRoomBackground({
   }, [interactive]);
 
   return (
-    <div ref={containerRef} className={cn("absolute inset-0 overflow-hidden", className)}>
+    <div
+      ref={containerRef}
+      className={cn("absolute inset-0 z-0 overflow-hidden", className)}
+    >
       {room.layers.map((layer, index) => (
         <div
           key={layer.id}