Keep the platform's footer always visible at the bottom of the screen

Update Footer component to use 'fixed bottom-0 left-0 right-0' CSS classes to ensure it remains fixed at the bottom of the viewport.

Replit-Commit-Author: Agent
Replit-Commit-Session-Id: 0fb68265-c270-4198-9584-3d9be9bddb41
Replit-Commit-Checkpoint-Type: full_checkpoint
Replit-Commit-Screenshot-Url: https://storage.googleapis.com/screenshot-production-us-central1/3df548ff-50ae-432f-9be4-25d34eccc983/0fb68265-c270-4198-9584-3d9be9bddb41/rOJiPGe

client/src/components/Footer.tsx

@@ -2,7 +2,7 @@ import logoWhite from "@assets/logo_white_1759167910147.png";
 
 export default function Footer() {
   return (
-    <footer className="bg-gray-900 border-t border-gray-700 mt-6">
+    <footer className="fixed bottom-0 left-0 right-0 bg-gray-900 border-t border-gray-700 z-40">
         <div className="max-w-7xl mx-auto px-4 py-4">
           {/* Logo and Social Icons */}
           <div className="flex items-center justify-between mb-3">