fix: gift code display + share modal backdrop

- Don't uppercase gift codes (tokens are case-sensitive base64)
- Lighten share modal backdrop (bg-dark-900/40 instead of bg-black/60)

src/pages/GiftResult.tsx

@@ -10,7 +10,7 @@ import { AnimatedCrossmark } from '@/components/ui/AnimatedCrossmark';
 import { cn } from '@/lib/utils';
 
 function formatGiftCode(token: string): string {
-  return `GIFT-${token.slice(0, 12).toUpperCase()}`;
+  return `GIFT-${token.slice(0, 12)}`;
 }
 
 const MAX_POLL_MS = 10 * 60 * 1000; // 10 minutes

src/pages/GiftSubscription.tsx

@@ -1015,7 +1015,7 @@ function ShareModal({ gift, onClose }: { gift: SentGift; onClose: () => void })
       onClick={onClose}
     >
       {/* Backdrop */}
-      <div className="absolute inset-0 bg-black/60 backdrop-blur-sm" />
+      <div className="absolute inset-0 bg-dark-900/40 backdrop-blur-sm" />
 
       {/* Modal content */}
       <motion.div
@@ -1131,7 +1131,7 @@ function SentGiftCard({ gift }: { gift: SentGift }) {
   const { t } = useTranslation();
   const [showShareModal, setShowShareModal] = useState(false);
 
-  const giftCode = `GIFT-${gift.token.slice(0, 12).toUpperCase()}`;
+  const giftCode = `GIFT-${gift.token.slice(0, 12)}`;
   const isActivated = isGiftActivated(gift);
   const isAvailable = !isActivated && isGiftAvailable(gift.status);