feat: Add code download functionality

Adds a new "Download Code" button to the code block component, allowing users to download the code displayed for offline use.

This feature enhances user convenience and provides a more versatile experience for exploring and utilizing code snippets.

src/components/Option/Playground/PlaygroundChat.tsx

@@ -61,10 +61,10 @@ export const PlaygroundChat = () => {
         )}
       </div>
       {!isAtBottom && (
-        <div className="fixed md:bottom-40 bottom-36 z-20 left-0 right-0 flex justify-center">
+        <div className="fixed bottom-36 z-20 left-0 right-0 flex justify-center">
           <button
             onClick={scrollToBottom}
-            className="bg-gray-100 border dark:border-gray-700 dark:bg-gray-800 p-1 rounded-full shadow-md hover:bg-gray-200 dark:hover:bg-gray-700 transition-colors duration-200">
+            className="bg-white border border-gray-100 dark:border-none dark:bg-white/20 p-1.5 rounded-full pointer-events-auto">
             <ChevronDown className="size-4 text-gray-600 dark:text-gray-300" />
           </button>
         </div>