fix(a11y): switch semantics for admin form toggles

Add role=switch + aria-checked + aria-label to 12 ad-hoc toggle buttons across admin
create/edit forms (AdminCampaignCreate/Edit, AdminPromocodeCreate, AdminPromoGroupCreate,
AdminPromoOfferTemplateEdit, AdminPaymentMethodEdit, AdminTariffCreate) so screen readers
announce on/off state (WCAG 4.1.2).

src/pages/AdminPaymentMethodEdit.tsx

@@ -207,6 +207,9 @@ export default function AdminPaymentMethodEdit() {
           </div>
           <button
             onClick={() => setIsEnabled(!isEnabled)}
+            role="switch"
+            aria-checked={isEnabled}
+            aria-label={t('admin.paymentMethods.methodEnabled')}
             className={`relative h-6 w-11 rounded-full transition-colors ${
               isEnabled ? 'bg-accent-500' : 'bg-dark-600'
             }`}
@@ -234,6 +237,8 @@ export default function AdminPaymentMethodEdit() {
           </div>
           <button
             onClick={() => setOpenUrlDirect(!openUrlDirect)}
+            role="switch"
+            aria-checked={openUrlDirect}
             className={`relative h-6 w-11 shrink-0 rounded-full transition-colors ${
               openUrlDirect ? 'bg-accent-500' : 'bg-dark-600'
             }`}