- Replace bare layout with table-based 600px card design
- Gray background, white content card, rounded corners
- Company logo in header (falls back to account name)
- Attribution footer inlined with subtle styling
- Add reusable _email_button partial (blue CTA, table-based)
- Update invitation, completed, documents_copy emails to use button
- Auto-convert submitter link to styled button in custom email bodies
- Remove deprecated _mailer_attribution and _email_attribution partials
- Preserve RTL support and all existing customization flows
Sebastian Noe