Improve auction page loading and add a close button to guides

Optimizes auction data fetching with increased staleTime and implements a close button for the auction guide page by replacing the BookOpen icon with an X icon.

Replit-Commit-Author: Agent
Replit-Commit-Session-Id: 9a264234-c5d7-4dcc-adf3-a954b149b30d
Replit-Commit-Checkpoint-Type: full_checkpoint
Replit-Commit-Screenshot-Url: https://storage.googleapis.com/screenshot-production-us-central1/3df548ff-50ae-432f-9be4-25d34eccc983/9a264234-c5d7-4dcc-adf3-a954b149b30d/CMG42YQ

client/src/pages/Auctions.tsx

@@ -99,10 +99,12 @@ export default function Auctions() {
 
   const { data: auctions = [], isLoading: auctionsLoading } = useQuery<Auction[]>({
     queryKey: ["/api/auctions"],
+    staleTime: 30000, // 30초 동안 캐시 유지
   });
 
   const { data: mediaOutlets = [] } = useQuery<MediaOutlet[]>({
     queryKey: ["/api/media-outlets"],
+    staleTime: 60000, // 1분 동안 캐시 유지
   });
 
   const bidMutation = useMutation({