Added mark_email_unread_outlined icon to the toolbar. Calls setFlag(seen:false)
then pops back to the list so the email reappears as unread.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Wrapped the stream body in RefreshIndicator calling syncEmails.
Empty-state is now a scrollable ListView so the pull gesture triggers
even when the folder contains no messages.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Added preview field to EmailThread (from latest email's preview via
_groupIntoThreads). Thread tiles now show subject + one-line body snippet.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
