Implement billing status feature in Telegram bot

- Added a new command `/billing` and a corresponding menu option for users with billing roles to check their payment status.
- Implemented `HandleBillingStatusAsync` method to retrieve and display billing information, including the payment expiration date and remaining time in a user-friendly format.
- Updated the main menu to conditionally show the billing status option based on the user's role.
- Enhanced the `PaidUntilBadge` component to format and display the remaining time until the next payment in both days and hours/minutes.
- Updated documentation to reflect the new billing status feature and its usage in the Telegram bot.

frontend/src/routes/billing.tsx

@@ -7,6 +7,7 @@ import { Card, CardContent, CardHeader, CardTitle } from '@/shared/ui/card'
 import { Badge } from '@/shared/ui/badge'
 import { Button } from '@/shared/ui/button'
 import { getMyBillingStatus } from '@/features/billing/api'
+import { PaidUntilBadge } from '@/features/billing/PaidUntilBadge'
 import { PaymentRequestPanel } from '@/features/billing/PaymentRequestPanel'
 
 export const Route = createFileRoute('/billing')({ component: BillingPage })
@@ -56,12 +57,13 @@ function BillingContent() {
               <CardTitle className="text-base">{t('billing.status')}</CardTitle>
               {data.suspended && <Badge variant="destructive">{t('billing.suspended')}</Badge>}
             </CardHeader>
-            <CardContent>
+            <CardContent className="flex flex-col gap-2">
               <p className="text-sm text-muted-foreground">
                 {data.paidUntil
                   ? t('billing.paidUntil', { date: new Date(data.paidUntil).toLocaleDateString() })
                   : t('billing.neverPaid')}
               </p>
+              {data.paidUntil && <PaidUntilBadge paidUntil={data.paidUntil} />}
             </CardContent>
           </Card>