feat: add admin traffic packages and device limit management UI

Add device limit +/- stepper, traffic packages display with inline
delete, add traffic dropdown from tariff config, translations for
ru/en/zh/fa.

src/locales/en.json

@@ -1967,7 +1967,17 @@
           "unavailable": "(unavailable)",
           "noActive": "No active subscription",
           "create": "Create subscription",
-          "creating": "Creating..."
+          "creating": "Creating...",
+          "trafficPackages": "Traffic packages",
+          "addTraffic": "Add traffic",
+          "selectPackage": "Select package",
+          "addButton": "Add",
+          "addTrafficNote": "Admin: free, valid 30 days",
+          "trafficRemoved": "Traffic package removed",
+          "trafficAdded": "Traffic package added",
+          "expired": "expired",
+          "daysLeft": "d left",
+          "deviceLimitUpdated": "Device limit updated"
         },
         "balance": {
           "current": "Current balance",

src/locales/fa.json

@@ -1666,7 +1666,17 @@
           "unavailable": "(غیرقابل دسترس)",
           "noActive": "اشتراک فعالی وجود ندارد",
           "create": "ایجاد اشتراک",
-          "creating": "در حال ایجاد..."
+          "creating": "در حال ایجاد...",
+          "trafficPackages": "بسته‌های ترافیک",
+          "addTraffic": "افزودن ترافیک",
+          "selectPackage": "انتخاب بسته",
+          "addButton": "افزودن",
+          "addTrafficNote": "مدیر: رایگان، ۳۰ روز اعتبار",
+          "trafficRemoved": "بسته ترافیک حذف شد",
+          "trafficAdded": "بسته ترافیک اضافه شد",
+          "expired": "منقضی شده",
+          "daysLeft": "روز باقیمانده",
+          "deviceLimitUpdated": "محدودیت دستگاه به‌روز شد"
         },
         "balance": {
           "current": "موجودی فعلی",

src/locales/ru.json

@@ -2493,7 +2493,17 @@
           "unavailable": "(недоступен)",
           "noActive": "Нет активной подписки",
           "create": "Создать подписку",
-          "creating": "Создание..."
+          "creating": "Создание...",
+          "trafficPackages": "Пакеты трафика",
+          "addTraffic": "Добавить трафик",
+          "selectPackage": "Выберите пакет",
+          "addButton": "Добавить",
+          "addTrafficNote": "Админ: бесплатно, действует 30 дней",
+          "trafficRemoved": "Пакет трафика удалён",
+          "trafficAdded": "Пакет трафика добавлен",
+          "expired": "истёк",
+          "daysLeft": "дн. осталось",
+          "deviceLimitUpdated": "Лимит устройств обновлён"
         },
         "balance": {
           "current": "Текущий баланс",

src/locales/zh.json

@@ -1665,7 +1665,17 @@
           "unavailable": "（不可用）",
           "noActive": "无活跃订阅",
           "create": "创建订阅",
-          "creating": "创建中..."
+          "creating": "创建中...",
+          "trafficPackages": "流量包",
+          "addTraffic": "添加流量",
+          "selectPackage": "选择套餐",
+          "addButton": "添加",
+          "addTrafficNote": "管理员：免费，有效期30天",
+          "trafficRemoved": "流量包已删除",
+          "trafficAdded": "流量包已添加",
+          "expired": "已过期",
+          "daysLeft": "天剩余",
+          "deviceLimitUpdated": "设备限制已更新"
         },
         "balance": {
           "current": "当前余额",