feat: implement header/footer visibility controls for checkout and thankyou pages

- Created LayoutWrapper component to conditionally render header/footer based on route
- Created MinimalHeader component (logo only)
- Created MinimalFooter component (trust badges + policy links)
- Created usePageVisibility hook to get visibility settings per page
- Wrapped ClassicLayout with LayoutWrapper for conditional rendering
- Header/footer visibility now controlled directly in React SPA
- Settings: show/minimal/hide for both header and footer
- Background color support for checkout and thankyou pages

admin-spa/src/routes/More/index.tsx

@@ -1,6 +1,6 @@
 import React, { useEffect } from 'react';
 import { useNavigate, Link } from 'react-router-dom';
-import { Tag, Settings as SettingsIcon, ChevronRight, Minimize2, LogOut, Sun, Moon, Monitor, ExternalLink } from 'lucide-react';
+import { Tag, Settings as SettingsIcon, Palette, ChevronRight, Minimize2, LogOut, Sun, Moon, Monitor, ExternalLink } from 'lucide-react';
 import { __ } from '@/lib/i18n';
 import { usePageHeader } from '@/contexts/PageHeaderContext';
 import { useApp } from '@/contexts/AppContext';
@@ -21,6 +21,12 @@ const menuItems: MenuItem[] = [
     description: __('Manage discount codes and promotions'),
     to: '/coupons'
   },
+  {
+    icon: <Palette className="w-5 h-5" />,
+    label: __('Appearance'),
+    description: __('Customize your store appearance'),
+    to: '/appearance'
+  },
   {
     icon: <SettingsIcon className="w-5 h-5" />,
     label: __('Settings'),