fix: encode certificate ID in QR code URL

- Use encodeURIComponent to properly encode certId
- Fixes QR code URLs with special characters like /, +, =
- QR codes now generate with properly encoded URLs (%2F, %2B, %3D)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

apps/hackathon/src/app/certificate/[certId]/page.tsx

@@ -44,7 +44,9 @@ const CertificatePage: FC = (): ReactElement => {
   // Generate QR Code
   useEffect(() => {
     if (certId) {
-      const certificateUrl = `${window.location.origin}/certificate/${certId}`;
+      // Use encodeURIComponent to properly encode the certId for the URL
+      const encodedCertId = encodeURIComponent(certId);
+      const certificateUrl = `${window.location.origin}/certificate/${encodedCertId}`;
       QRCode.toDataURL(certificateUrl, {
         width: 200,
         margin: 1,