This fixes the 'data must be a String, QRSegment, or an Array' error that was
preventing checkout completion.
Changes:
- Move email sending outside payment transaction to avoid rollback on email failure
- Add error handling around PDF generation in mailers
- Improve QR code data building with multiple fallback strategies
- Use direct foreign key access instead of through associations for reliability
- Add comprehensive logging for debugging QR code issues
- Ensure checkout succeeds even if email/PDF generation fails
The payment process will now complete successfully regardless of email issues,
while still attempting to send confirmation emails with PDF attachments.
c3f5d72a91