fix(kiosk): Increase QR code size to 320px with fixed dimensions

- Removed maxWidth constraint that caused scaling
- Set explicit height/width to prevent shrinking

frontend/src/pages/VisitorKioskPage.tsx

@@ -542,16 +542,13 @@ export default function VisitorKioskPage() {
 
                             {successData.badgeNumber && ( // Only show QR for Check-IN, not Check-OUT
                                 <div className="mt-8 space-y-6">
-                                    <div className="inline-block bg-white p-6 rounded-2xl shadow-2xl">
-                                        <div style={{ height: "auto", margin: "0 auto", width: 280 }}>
+                                    <div className="inline-block bg-white p-8 rounded-3xl shadow-2xl">
                                         <QRCode
-                                                size={280}
-                                                style={{ height: "auto", maxWidth: "100%", width: "100%" }}
+                                            size={320}
+                                            style={{ height: 320, width: 320 }}
                                             value={`${window.location.origin}/badges/${successData.visitId || 'demo-token'}`}
-                                                viewBox={`0 0 280 280`}
                                         />
                                     </div>
-                                    </div>
 
                                     <div>
                                         <p className="text-white font-bold text-lg mb-1">Scan for Digital Badge</p>