feat: add per-channel disable settings and global settings to channel admin

- Add global settings section (CHANNEL_IS_REQUIRED_SUB, trial/paid toggles)
  at top of AdminChannelSubscriptions page
- Add per-channel disable_trial_on_leave and disable_paid_on_leave toggles
  in each channel card with inline Toggle controls
- Update RequiredChannel type and API request interfaces with new fields
- Add translations for globalSettings and perChannel in en/ru/fa/zh locales

src/locales/en.json

@@ -1322,6 +1322,21 @@
         "submit": "Add",
         "save": "Save",
         "cancel": "Cancel"
+      },
+      "globalSettings": {
+        "title": "Channel Settings",
+        "channelRequired": "Require subscription",
+        "channelRequiredDesc": "Users must subscribe to channels to use the bot",
+        "disableTrialOnUnsub": "Disable trial on unsubscribe",
+        "disableTrialOnUnsubDesc": "Revoke trial access when user unsubscribes from any channel",
+        "requiredForAll": "Required for all users",
+        "requiredForAllDesc": "Apply channel subscription check to all users, including paid"
+      },
+      "perChannel": {
+        "disableTrial": "Disable trial on leave",
+        "disableTrialDesc": "Revoke trial when user leaves this channel",
+        "disablePaid": "Disable paid on leave",
+        "disablePaidDesc": "Revoke paid access when user leaves this channel"
       }
     },
     "settings": {

src/locales/fa.json

@@ -1025,6 +1025,21 @@
         "submit": "افزودن",
         "save": "ذخیره",
         "cancel": "لغو"
+      },
+      "globalSettings": {
+        "title": "تنظیمات کانال",
+        "channelRequired": "الزام عضویت",
+        "channelRequiredDesc": "کاربران باید در کانال‌ها عضو شوند تا از ربات استفاده کنند",
+        "disableTrialOnUnsub": "غیرفعال‌سازی آزمایشی هنگام لغو عضویت",
+        "disableTrialOnUnsubDesc": "لغو دسترسی آزمایشی هنگام لغو عضویت از هر کانال",
+        "requiredForAll": "اجباری برای همه",
+        "requiredForAllDesc": "بررسی عضویت برای همه کاربران، از جمله پولی"
+      },
+      "perChannel": {
+        "disableTrial": "غیرفعال‌سازی آزمایشی هنگام خروج",
+        "disableTrialDesc": "لغو دسترسی آزمایشی هنگام خروج از این کانال",
+        "disablePaid": "غیرفعال‌سازی پولی هنگام خروج",
+        "disablePaidDesc": "لغو دسترسی پولی هنگام خروج از این کانال"
       }
     },
     "payments": {

src/locales/ru.json

@@ -1348,6 +1348,21 @@
         "submit": "Добавить",
         "save": "Сохранить",
         "cancel": "Отмена"
+      },
+      "globalSettings": {
+        "title": "Настройки каналов",
+        "channelRequired": "Требовать подписку",
+        "channelRequiredDesc": "Пользователи должны подписаться на каналы для использования бота",
+        "disableTrialOnUnsub": "Отключать триал при отписке",
+        "disableTrialOnUnsubDesc": "Отзывать пробный доступ при отписке от любого канала",
+        "requiredForAll": "Обязательно для всех",
+        "requiredForAllDesc": "Проверять подписку для всех пользователей, включая платных"
+      },
+      "perChannel": {
+        "disableTrial": "Отключать триал при выходе",
+        "disableTrialDesc": "Отзывать пробный доступ при выходе из этого канала",
+        "disablePaid": "Отключать платный при выходе",
+        "disablePaidDesc": "Отзывать платный доступ при выходе из этого канала"
       }
     },
     "settings": {

src/locales/zh.json

@@ -1077,6 +1077,21 @@
         "submit": "添加",
         "save": "保存",
         "cancel": "取消"
+      },
+      "globalSettings": {
+        "title": "频道设置",
+        "channelRequired": "要求订阅",
+        "channelRequiredDesc": "用户必须订阅频道才能使用机器人",
+        "disableTrialOnUnsub": "取消订阅时禁用试用",
+        "disableTrialOnUnsubDesc": "用户取消订阅任何频道时撤销试用权限",
+        "requiredForAll": "对所有用户强制",
+        "requiredForAllDesc": "对所有用户（包括付费用户）检查频道订阅"
+      },
+      "perChannel": {
+        "disableTrial": "退出时禁用试用",
+        "disableTrialDesc": "用户退出此频道时撤销试用权限",
+        "disablePaid": "退出时禁用付费",
+        "disablePaidDesc": "用户退出此频道时撤销付费权限"
       }
     },
     "settings": {