Clean up UI: remove unnecessary text and elements

- Remove 'AI Trading Dashboard' hero section from overview page
- Remove 'Advanced cryptocurrency trading...' description from overview
- Remove 'Manual Trading' header and description from trading page
- Remove 'Refresh Balance' button functionality
- Remove symbol selection interface and related state management
- Remove wallet overview section to prevent runtime errors
- Simplify trading page to focus on core trading panels only

Result: Cleaner, more focused user interface with streamlined navigation

app/page.js

@@ -5,16 +5,6 @@ import StatusOverview from '../components/StatusOverview.js'
 export default function HomePage() {
   return (
     <div className="space-y-8">
-      {/* Hero Section */}
-      <div className="text-center py-8">
-        <h1 className="text-4xl font-bold bg-gradient-to-r from-cyan-400 to-blue-600 bg-clip-text text-transparent mb-4">
-          AI Trading Dashboard
-        </h1>
-        <p className="text-gray-400 text-lg max-w-2xl mx-auto">
-          Advanced cryptocurrency trading with AI-powered analysis, automated execution, and real-time monitoring.
-        </p>
-      </div>
-      
       {/* Status Overview */}
       <StatusOverview />