Upstream changes:
- Template revision history (save/view/revert template versions)
- HMAC webhook signature validation
- i18n fixes and updates
- Gem updates (hexapdf, nokogiri, net-imap)
- PDF rotation via pdfium
- Allow permanent delete of submissions in archived templates
- Retry webhooks in test mode
- Various bug fixes and style adjustments
Fork features preserved:
- Teams & Editor Role
- Email reminders
- Company logo / white-label
- Custom email templates
- Template creation API
- Navigation customization