- Remove duplicate action bar from MailDetail (actions are in global plugin toolbar)
- Change iframe sandbox from "" to "allow-same-origin" so height auto-resize works
- Move attachments inside the scrollable body container so they are visible
- Remove unused imports (clsx, Badge) and unused destructured props
- Fix FlagUpdatePayload field names to match backend schema (is_seen/is_flagged)
- Replace dangerouslySetInnerHTML with sandboxed iframe (srcDoc, sandbox="")
- Add bulk mark read/unread with checkbox selection in MailList
- Add floating bulk action bar in Mail.tsx
- Add imap_sync_mail_flags() to push Seen/Flagged flags to IMAP server
- Call IMAP flag sync in PATCH /flags endpoint
- Add i18n keys for bulk actions (de/en)