refactor: extract promo offers modals to separate pages

- Create AdminPromoOfferTemplateEdit.tsx for template editing
- Create AdminPromoOfferSend.tsx for sending offers with result screen
- Add routes for /admin/promo-offers/templates/:id/edit and /admin/promo-offers/send
- Simplify AdminPromoOffers.tsx by removing modals
- Add i18n keys for new pages

src/locales/en.json

@@ -1828,6 +1828,10 @@
         "notificationsFailed": "(failed: {{count}})",
         "sendError": "Failed to send offer"
       },
+      "notFound": "Template not found",
+      "noActiveTemplates": "No active templates",
+      "backToList": "Back to offers",
+      "sendAnother": "Send another",
       "actions": {
         "created": "Created",
         "claimed": "Claimed",

src/locales/fa.json

@@ -1621,6 +1621,10 @@
         "notificationsFailed": "(ناموفق: {{count}})",
         "sendError": "ارسال پیشنهاد ناموفق بود"
       },
+      "notFound": "قالب یافت نشد",
+      "noActiveTemplates": "قالب فعالی وجود ندارد",
+      "backToList": "بازگشت به لیست پیشنهادات",
+      "sendAnother": "ارسال دیگری",
       "actions": {
         "created": "ایجاد شده",
         "claimed": "فعال شده",

src/locales/ru.json

@@ -2339,6 +2339,10 @@
         "notificationsFailed": "(не доставлено: {{count}})",
         "sendError": "Не удалось отправить предложение"
       },
+      "notFound": "Шаблон не найден",
+      "noActiveTemplates": "Нет активных шаблонов",
+      "backToList": "К списку предложений",
+      "sendAnother": "Отправить еще",
       "actions": {
         "created": "Создано",
         "claimed": "Активировано",

src/locales/zh.json

@@ -1620,6 +1620,10 @@
         "notificationsFailed": "（失败: {{count}}）",
         "sendError": "发送优惠失败"
       },
+      "notFound": "未找到模板",
+      "noActiveTemplates": "没有活跃的模板",
+      "backToList": "返回优惠列表",
+      "sendAnother": "再发送一个",
       "actions": {
         "created": "已创建",
         "claimed": "已领取",