Refactor client update handling to support nullable parameters for name and expiration

- Updated the `UpdateClientAsync` method in `IXuiPanelGateway` to accept nullable parameters for `name` and `expiresAt`, allowing for more flexible client management without unintended modifications.
- Adjusted the `BlockUserCommandHandler`, `UnblockUserCommandHandler`, and other related command handlers to utilize the new nullable parameters, ensuring that client names remain unchanged during block/unblock operations and that expiration dates are managed correctly.
- Enhanced the billing and configuration handling to reflect the new logic for managing client states based on expiration rather than enabling/disabling, improving reliability in client status management.
- Updated tests to cover the new behavior and ensure proper functionality across the application.

frontend/src/features/configs/CreateConfigDialog.tsx

@@ -1,5 +1,6 @@
 import { useState } from 'react'
 import { useMutation, useQueryClient } from '@tanstack/react-query'
+import { useNavigate } from '@tanstack/react-router'
 import { useTranslation } from 'react-i18next'
 import { Plus } from 'lucide-react'
 import { toast } from '@/shared/ui/toast-store'
@@ -15,6 +16,7 @@ import { createConfig } from './api'
 export function CreateConfigDialog({ inbounds }: { inbounds: AvailableInboundDto[] }) {
   const { t } = useTranslation()
   const queryClient = useQueryClient()
+  const navigate = useNavigate()
   const [open, setOpen] = useState(false)
   const [inboundId, setInboundId] = useState('')
   const [label, setLabel] = useState('')
@@ -29,6 +31,15 @@ export function CreateConfigDialog({ inbounds }: { inbounds: AvailableInboundDto
       setLabel('')
     },
     onError: (error) => {
+      // Safety-net: дашборд уже скрывает эту кнопку при истёкшей оплате (см. dashboard.tsx), но
+      // между открытием страницы и отправкой формы биллинг мог протухнуть — сервер всё равно
+      // проверяет (ConfigErrors.BillingRequired) и на всякий случай отправляем на оплату.
+      if (error instanceof HttpError && error.title === 'Configs.BillingRequired') {
+        toast.error(t('configs.billingRequiredNotice'))
+        setOpen(false)
+        void navigate({ to: '/billing' })
+        return
+      }
       const message =
         error instanceof HttpError && error.status === 409 ? t('configs.quotaExceeded') : t('auth.genericError')
       toast.error(message)