feat: auto-close modals when success notification appears

- Add closeOthersSignal to success notification store
- Create useCloseOnSuccessNotification hook for modals to subscribe
- Update TopUpModal to auto-close on success events
- Update InsufficientBalancePrompt to auto-close on success events
- Update Subscription page to close all modals/forms on success events

This ensures that when a WebSocket event indicates successful payment
or subscription purchase, all related modals close automatically,
providing clear feedback to users.

src/components/TopUpModal.tsx

@@ -6,6 +6,7 @@ import { balanceApi } from '../api/balance';
 import { useCurrency } from '../hooks/useCurrency';
 import { useTelegramWebApp } from '../hooks/useTelegramWebApp';
 import { checkRateLimit, getRateLimitResetTime, RATE_LIMIT_KEYS } from '../utils/rateLimit';
+import { useCloseOnSuccessNotification } from '../store/successNotification';
 import type { PaymentMethod } from '../types';
 import BentoCard from './ui/BentoCard';
 
@@ -144,6 +145,9 @@ export default function TopUpModal({ method, onClose, initialAmountRubles }: Top
     onClose();
   }, [onClose]);
 
+  // Auto-close when success notification appears (e.g., balance topped up via WebSocket)
+  useCloseOnSuccessNotification(handleClose);
+
   // Keyboard: Escape to close (PC)
   useEffect(() => {
     const handleKeyDown = (e: KeyboardEvent) => {