feat: enhance UI with Lucide icons across various components

- add logo
- Replaced emoji placeholders with Lucide icons in AITradersPage, CompetitionPage, EquityChart, Header, LoginPage, and RegisterPage for improved visual consistency.
- Updated button styles to include icons for actions like adding models and exchanges.
- Enhanced error and empty state displays with relevant icons to provide better user feedback.

web/src/components/LoginPage.tsx

@@ -3,6 +3,7 @@ import { useAuth } from '../contexts/AuthContext';
 import { useLanguage } from '../contexts/LanguageContext';
 import { t } from '../i18n/translations';
 import { Header } from './Header';
+import { Zap, Smartphone } from 'lucide-react';
 
 export function LoginPage() {
   const { language } = useLanguage();
@@ -57,9 +58,9 @@ export function LoginPage() {
         <div className="w-full max-w-md">
           {/* Logo */}
           <div className="text-center mb-8">
-            <div className="w-16 h-16 rounded-full mx-auto mb-4 flex items-center justify-center text-3xl"
+            <div className="w-16 h-16 rounded-full mx-auto mb-4 flex items-center justify-center"
                  style={{ background: 'linear-gradient(135deg, #F0B90B 0%, #FCD535 100%)' }}>
-              ⚡
+              <Zap className="w-8 h-8" style={{ color: '#000' }} />
             </div>
             <h1 className="text-2xl font-bold" style={{ color: '#EAECEF' }}>
               {t('loginTitle', language)}
@@ -121,7 +122,9 @@ export function LoginPage() {
           ) : (
             <form onSubmit={handleOTPVerify} className="space-y-4">
               <div className="text-center mb-4">
-                <div className="text-4xl mb-2">📱</div>
+                <div className="mb-2 flex justify-center">
+                  <Smartphone className="w-10 h-10" style={{ color: '#F0B90B' }} />
+                </div>
                 <p className="text-sm" style={{ color: '#848E9C' }}>
                   {t('scanQRCodeInstructions', language)}<br />
                   {t('enterOTPCode', language)}