refactor: consolidate icons and move server edit to separate page

- Create centralized icons file at src/components/icons/index.tsx
- Update admin and AppShell icons to re-export from centralized location
- Replace trial "T" button with GiftIcon in AdminServers
- Move server editing from modal to dedicated page /admin/servers/:id/edit
- Add localization keys for server edit page (mainSettings, pricingAndLimits, updateError)

src/components/PromoOffersSection.tsx

@@ -3,23 +3,7 @@ import { useQuery, useMutation, useQueryClient } from '@tanstack/react-query';
 import { useTranslation } from 'react-i18next';
 import { Link } from 'react-router-dom';
 import { promoApi, PromoOffer } from '../api/promo';
-
-// Icons
-const ClockIcon = () => (
-  <svg className="h-4 w-4" fill="none" viewBox="0 0 24 24" stroke="currentColor" strokeWidth={2}>
-    <path
-      strokeLinecap="round"
-      strokeLinejoin="round"
-      d="M12 6v6h4.5m4.5 0a9 9 0 11-18 0 9 9 0 0118 0z"
-    />
-  </svg>
-);
-
-const CheckIcon = () => (
-  <svg className="h-5 w-5" fill="none" viewBox="0 0 24 24" stroke="currentColor" strokeWidth={2}>
-    <path strokeLinecap="round" strokeLinejoin="round" d="M4.5 12.75l6 6 9-13.5" />
-  </svg>
-);
+import { ClockIcon, CheckIcon } from './icons';
 
 // Helper functions
 const formatTimeLeft = (