feat: Multiple fixes and features

1. Add allow_custom_avatar toggle to Customer Settings
2. Implement coupon apply/remove in Cart and Checkout pages
3. Update Cart interface with coupons array and discount_total
4. Implement Downloads page to fetch from /account/downloads API

admin-spa/src/routes/Settings/Customers.tsx

@@ -13,6 +13,7 @@ import { formatMoney, getStoreCurrency } from '@/lib/currency';
 interface CustomerSettings {
   auto_register_members: boolean;
   multiple_addresses_enabled: boolean;
+  allow_custom_avatar: boolean;
   vip_min_spent: number;
   vip_min_orders: number;
   vip_timeframe: 'all' | '30' | '90' | '365';
@@ -24,6 +25,7 @@ export default function CustomersSettings() {
   const [settings, setSettings] = useState<CustomerSettings>({
     auto_register_members: false,
     multiple_addresses_enabled: true,
+    allow_custom_avatar: false,
     vip_min_spent: 1000,
     vip_min_orders: 10,
     vip_timeframe: 'all',
@@ -138,6 +140,14 @@ export default function CustomersSettings() {
             onCheckedChange={(checked) => setSettings({ ...settings, multiple_addresses_enabled: checked })}
           />
 
+          <ToggleField
+            id="allow_custom_avatar"
+            label={__('Allow custom profile photo')}
+            description={__('Allow customers to upload their own profile photo. When disabled, customer avatars will use Gravatar or default initials.')}
+            checked={settings.allow_custom_avatar}
+            onCheckedChange={(checked) => setSettings({ ...settings, allow_custom_avatar: checked })}
+          />
+
 
         </div>
       </SettingsCard>