feat: integrate Stripe payment with bugfixes and active timeout cancellation

- Add Stripe payment provider with Checkout Session flow
- Payment provider abstraction layer (EasyPay + Stripe unified interface)
- Stripe webhook with proper raw body handling and signature verification
- Frontend: Stripe button with URL validation, anti-duplicate click, noopener
- Active timeout cancellation: query platform before expiring, recover paid orders
- Singleton Stripe client, idempotency keys, Math.round for amounts
- Handle async_payment events, return null for unknown webhook events
- Set Checkout Session expires_at aligned with order timeout
- Add cancelPayment to provider interface (Stripe: sessions.expire, EasyPay: no-op)
- Enable stripe in frontend payment type list

src/components/OrderSummaryCards.tsx

@@ -11,7 +11,10 @@ interface OrderSummaryCardsProps {
 }
 
 export default function OrderSummaryCards({ isDark, summary }: OrderSummaryCardsProps) {
-  const cardClass = ['rounded-xl border p-3', isDark ? 'border-slate-700 bg-slate-800/70' : 'border-slate-200 bg-slate-50'].join(' ');
+  const cardClass = [
+    'rounded-xl border p-3',
+    isDark ? 'border-slate-700 bg-slate-800/70' : 'border-slate-200 bg-slate-50',
+  ].join(' ');
   const labelClass = ['text-xs', isDark ? 'text-slate-400' : 'text-slate-500'].join(' ');
 
   return (