Fix TypeScript error in qrDataValidator - use issues instead of errors

Zod v3 uses 'issues' property instead of 'errors' for ZodError.
This fixes the production build failure.

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

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

src/utils/qrDataValidator.ts

@@ -79,7 +79,7 @@ export function validateQRData(data: unknown): QRValidationResult {
     };
   } catch (error) {
     if (error instanceof z.ZodError) {
-      const errorMessages = error.errors.map((err) => {
+      const errorMessages = error.issues.map((err) => {
         const path = err.path.join('.');
         return `${path ? path + ': ' : ''}${err.message}`;
       });