feat: add success notification modal for balance and subscription events

- Add zustand store for global success notifications
- Create SuccessNotificationModal component with prominent UI
- Update WebSocketNotifications to show modal for important events:
  - balance.topup shows balance topped up modal
  - subscription.activated shows activation modal
  - subscription.renewed shows renewal modal
- Add translations for all locales (ru, en, zh, fa)

src/locales/fa.json

@@ -114,6 +114,27 @@
       "receivedMessage": "پرداخت {{amount}} {{currency}} دریافت شد"
     }
   },
+  "successNotification": {
+    "balanceTopup": {
+      "title": "موجودی شارژ شد!"
+    },
+    "subscriptionActivated": {
+      "title": "اشتراک فعال شد!"
+    },
+    "subscriptionRenewed": {
+      "title": "اشتراک تمدید شد!"
+    },
+    "subscriptionPurchased": {
+      "title": "اشتراک خریداری شد!"
+    },
+    "amount": "مبلغ",
+    "price": "قیمت",
+    "newBalance": "موجودی جدید",
+    "tariff": "تعرفه",
+    "validUntil": "معتبر تا",
+    "goToSubscription": "رفتن به اشتراک",
+    "goToBalance": "رفتن به موجودی"
+  },
   "auth": {
     "login": "ورود",
     "register": "ثبت نام",