fix: restore panel user discovery on admin tariff change, localize cart reminder

Bug 1: Admin tariff change used update_remnawave_user() which returns
early when user has no remnawave_uuid. Restored _sync_subscription_to_panel()
which discovers/creates panel users via telegram_id/email fallback, then
applies traffic reset if RESET_TRAFFIC_ON_TARIFF_SWITCH is enabled.

Bug 2: Post-topup cart reminder in payment/common.py had hardcoded Russian
text sent to all users regardless of language. Replaced with localized
BALANCE_TOPPED_UP_CART_SUFFICIENT/INSUFFICIENT keys and used existing
MY_BALANCE_BUTTON/MAIN_MENU_BUTTON for inline keyboard buttons.
Added new i18n keys to all 5 locales (ru, en, ua, zh, fa).

app/cabinet/routes/admin_users.py

@@ -1073,17 +1073,19 @@ async def update_user_subscription(
         await db.commit()
         await db.refresh(subscription)
 
-        # Синхронизируем с RemnaWave (сброс трафика по админ-настройке)
+        # Синхронизируем с RemnaWave (discovery/create + сброс трафика по админ-настройке)
         try:
-            from app.services.subscription_service import SubscriptionService
+            result = await _sync_subscription_to_panel(db, user, subscription)
+            if settings.RESET_TRAFFIC_ON_TARIFF_SWITCH and result.get('action') in ('updated', 'created'):
+                from app.services.subscription_service import SubscriptionService
 
-            subscription_service = SubscriptionService()
-            await subscription_service.update_remnawave_user(
-                db,
-                subscription,
-                reset_traffic=settings.RESET_TRAFFIC_ON_TARIFF_SWITCH,
-                reset_reason='смена тарифа (cabinet admin)',
-            )
+                subscription_service = SubscriptionService()
+                await subscription_service.update_remnawave_user(
+                    db,
+                    subscription,
+                    reset_traffic=True,
+                    reset_reason='смена тарифа (cabinet admin)',
+                )
         except Exception as e:
             logger.error('Failed to sync tariff switch with RemnaWave', error=e)
 

app/localization/locales/en.json

@@ -1328,6 +1328,8 @@
   "RESET_TRAFFIC_BUTTON": "🔄 Reset traffic",
   "NO_SAVED_SUBSCRIPTION_ORDER": "No pending subscription order was found.",
   "RETURN_TO_SUBSCRIPTION_CHECKOUT": "⬅️ Return to subscription checkout",
+  "BALANCE_TOPPED_UP_CART_SUFFICIENT": "✅ Balance topped up by {amount}!\n\n💰 Current balance: {balance}\n\n🛒 You have a saved cart for {cart_total}\nYour balance is sufficient to proceed.",
+  "BALANCE_TOPPED_UP_CART_INSUFFICIENT": "✅ Balance topped up by {amount}!\n\n💰 Current balance: {balance}\n\n🛒 You have a saved cart for {cart_total}\nStill needed: {missing}",
   "RULES_ACCEPT": "✅ I accept the rules",
   "RULES_ACCEPTED_PROCESSING": "✅ Rules accepted! Completing registration...",
   "RULES_DECLINE": "❌ I do not accept",

app/localization/locales/fa.json

@@ -1349,6 +1349,8 @@
     "RESET_TRAFFIC_BUTTON": "🔄 بازنشانی ترافیک",
     "NO_SAVED_SUBSCRIPTION_ORDER": "❗️ سفارش ذخیره‌شده یافت نشد.",
     "RETURN_TO_SUBSCRIPTION_CHECKOUT": "⬅️ بازگشت به خرید اشتراک",
+    "BALANCE_TOPPED_UP_CART_SUFFICIENT": "✅ موجودی شارژ شد به مبلغ {amount}!\n\n💰 موجودی فعلی: {balance}\n\n🛒 شما یک سبد ذخیره‌شده به مبلغ {cart_total} دارید\nموجودی شما برای ادامه کافی است.",
+    "BALANCE_TOPPED_UP_CART_INSUFFICIENT": "✅ موجودی شارژ شد به مبلغ {amount}!\n\n💰 موجودی فعلی: {balance}\n\n🛒 شما یک سبد ذخیره‌شده به مبلغ {cart_total} دارید\nمبلغ باقیمانده: {missing}",
     "RULES_ACCEPT": "✅ می‌پذیرم",
     "RULES_ACCEPTED_PROCESSING": "✅ قوانین پذیرفته شد. در حال پردازش...",
     "RULES_DECLINE": "❌ نمی‌پذیرم",

app/localization/locales/ru.json

@@ -1349,6 +1349,8 @@
   "RESET_TRAFFIC_BUTTON": "🔄 Сбросить трафик",
   "NO_SAVED_SUBSCRIPTION_ORDER": "❗️ Сохраненный заказ не найден.",
   "RETURN_TO_SUBSCRIPTION_CHECKOUT": "⬅️ Вернуться к оформлению подписки",
+  "BALANCE_TOPPED_UP_CART_SUFFICIENT": "✅ Баланс пополнен на {amount}!\n\n💰 Текущий баланс: {balance}\n\n🛒 У вас есть сохранённая корзина на {cart_total}\nСредств на балансе достаточно для оформления.",
+  "BALANCE_TOPPED_UP_CART_INSUFFICIENT": "✅ Баланс пополнен на {amount}!\n\n💰 Текущий баланс: {balance}\n\n🛒 У вас есть сохранённая корзина на {cart_total}\nНе хватает: {missing}",
   "RULES_ACCEPT": "✅ Принимаю правила",
   "RULES_ACCEPTED_PROCESSING": "✅ Правила приняты! Завершаем регистрацию...",
   "RULES_DECLINE": "❌ Не принимаю",

app/localization/locales/ua.json

@@ -1265,6 +1265,8 @@
  "RESET_TRAFFIC_BUTTON": "🔄 Скинути трафік",
  "NO_SAVED_SUBSCRIPTION_ORDER": "❗️ Збережене замовлення не знайдено.",
   "RETURN_TO_SUBSCRIPTION_CHECKOUT": "⬅️ Повернутися до оформлення підписки",
+  "BALANCE_TOPPED_UP_CART_SUFFICIENT": "✅ Баланс поповнено на {amount}!\n\n💰 Поточний баланс: {balance}\n\n🛒 У вас є збережений кошик на {cart_total}\nКоштів на балансі достатньо для оформлення.",
+  "BALANCE_TOPPED_UP_CART_INSUFFICIENT": "✅ Баланс поповнено на {amount}!\n\n💰 Поточний баланс: {balance}\n\n🛒 У вас є збережений кошик на {cart_total}\nНе вистачає: {missing}",
  "RULES_ACCEPT": "✅ Приймаю правила",
  "RULES_ACCEPTED_PROCESSING": "✅ Правила прийнято! Завершуємо реєстрацію...",
  "RULES_DECLINE": "❌ Не приймаю",

app/services/payment/common.py

@@ -341,20 +341,15 @@ async def send_cart_notification_after_topup(
     texts = get_texts(getattr(user, 'language', 'ru'))
 
     # Build message based on whether balance is sufficient
+    fmt = settings.format_price
     if balance >= cart_total:
-        message_text = (
-            f'✅ Баланс пополнен на {settings.format_price(amount_kopeks)}!\n\n'
-            f'💰 Текущий баланс: {settings.format_price(balance)}\n\n'
-            f'🛒 У вас есть сохранённая корзина на {settings.format_price(cart_total)}\n'
-            f'Средств на балансе достаточно для оформления.'
-        )
+        template = texts.get('BALANCE_TOPPED_UP_CART_SUFFICIENT', '')
+        message_text = template.format(amount=fmt(amount_kopeks), balance=fmt(balance), cart_total=fmt(cart_total))
     else:
         missing = cart_total - balance
-        message_text = (
-            f'✅ Баланс пополнен на {settings.format_price(amount_kopeks)}!\n\n'
-            f'💰 Текущий баланс: {settings.format_price(balance)}\n\n'
-            f'🛒 У вас есть сохранённая корзина на {settings.format_price(cart_total)}\n'
-            f'Не хватает: {settings.format_price(missing)}'
+        template = texts.get('BALANCE_TOPPED_UP_CART_INSUFFICIENT', '')
+        message_text = template.format(
+            amount=fmt(amount_kopeks), balance=fmt(balance), cart_total=fmt(cart_total), missing=fmt(missing),
         )
 
     keyboard = types.InlineKeyboardMarkup(
@@ -365,8 +360,8 @@ async def send_cart_notification_after_topup(
                     callback_data='return_to_saved_cart',
                 )
             ],
-            [types.InlineKeyboardButton(text='💰 Мой баланс', callback_data='menu_balance')],
-            [types.InlineKeyboardButton(text='🏠 Главное меню', callback_data='back_to_menu')],
+            [types.InlineKeyboardButton(text=texts.MY_BALANCE_BUTTON, callback_data='menu_balance')],
+            [types.InlineKeyboardButton(text=texts.MAIN_MENU_BUTTON, callback_data='back_to_menu')],
         ]
     )