Fix auction guide page navigation and visual bug

Update AuctionGuide.tsx to fix a visual bug with the triangle indicator and implement a functional back navigation using `window.history.back()` when the book icon is clicked.

Replit-Commit-Author: Agent
Replit-Commit-Session-Id: 069d4324-6c40-4355-955e-c714a50de1ea
Replit-Commit-Checkpoint-Type: full_checkpoint
Replit-Commit-Screenshot-Url: https://storage.googleapis.com/screenshot-production-us-central1/3df548ff-50ae-432f-9be4-25d34eccc983/069d4324-6c40-4355-955e-c714a50de1ea/UXwUwik

.replit

@@ -22,6 +22,10 @@ externalPort = 3002
 localPort = 37531
 externalPort = 3001
 
+[[ports]]
+localPort = 40661
+externalPort = 3003
+
 [[ports]]
 localPort = 43349
 externalPort = 3000

client/src/pages/AuctionGuide.tsx

@@ -12,6 +12,10 @@ import {
 } from "lucide-react";
 
 export default function AuctionGuide() {
+  const handleGoBack = () => {
+    window.history.back();
+  };
+
   return (
     <div className="min-h-screen bg-gray-50">
       {/* Header */}
@@ -33,18 +37,17 @@ export default function AuctionGuide() {
                   variant="ghost" 
                   size="sm"
                   className="relative"
+                  onClick={handleGoBack}
                   data-testid="button-auction-guide"
                 >
                   <BookOpen className="h-4 w-4" />
                 </Button>
                 {/* Triangle indicator */}
-                <div className="absolute left-1/2 -translate-x-1/2 top-full">
-                  <svg width="16" height="8" viewBox="0 0 16 8" className="text-gray-50">
-                    <path 
-                      d="M 8 0 Q 8 2, 6 3 L 2 7 Q 0 8, 0 8 L 16 8 Q 16 8, 14 7 L 10 3 Q 8 2, 8 0 Z" 
-                      fill="currentColor"
+                <div className="absolute left-1/2 -translate-x-1/2 top-full z-10">
+                  <div 
+                    className="w-0 h-0 border-l-[12px] border-l-transparent border-r-[12px] border-r-transparent border-b-[10px] border-b-gray-50"
+                    style={{ filter: 'drop-shadow(0 -1px 0px rgba(229, 231, 235, 1))' }}
                   />
-                  </svg>
                 </div>
               </div>