feat: add LIMITED subscription status support with traffic-exhausted UX

- Add is_limited to Subscription type
- Show yellow traffic-exhausted badge on Subscription and AdminUsers pages
- SubscriptionCardExpired: amber theme with warning icon and buy-traffic CTA for limited
- Dashboard: route limited subscriptions to SubscriptionCardExpired
- Subscription page: show additional options (buy traffic) for limited subs
- Use is_limited boolean instead of status string comparison
- Add trafficLimited translations for ru, en, zh, fa
- AdminUserDetail StatusBadge: add limited yellow styling

src/pages/AdminUserDetail.tsx

@@ -119,6 +119,7 @@ function StatusBadge({ status }: { status: string }) {
     deleted: 'bg-dark-600 text-dark-400 border-dark-500',
     trial: 'bg-accent-500/20 text-accent-400 border-accent-500/30',
     expired: 'bg-warning-500/20 text-warning-400 border-warning-500/30',
+    limited: 'bg-yellow-500/20 text-yellow-400 border-yellow-500/30',
     disabled: 'bg-dark-600 text-dark-400 border-dark-500',
   };