feat(SerialConsolePage): enhance terminal layout with background icon and improved styling

src/app/components/SerialConsolePage.tsx

@@ -137,10 +137,16 @@ export default function SerialConsolePage({ onBack }: Props) {
 
       {/* Terminal */}
       <div
-        ref={containerRef}
-        className="flex-1 min-h-0"
+        className="flex-1 min-h-0 relative overflow-hidden"
         style={{ paddingBottom: 'env(safe-area-inset-bottom)' }}
+      >
+        <div ref={containerRef} className="absolute inset-0" />
+        <img
+          src="assets/icon.svg"
+          className="absolute inset-0 m-auto w-64 h-64 pointer-events-none select-none opacity-40 z-10"
+          aria-hidden="true"
         />
       </div>
+    </div>
   );
 }