When archiving selected mails and the archive folder doesn't exist, show
a dialog asking the user to either choose an existing folder or create a
new one. When creating, the JMAP role is sent to the server and the
IMAP/JMAP role is stored in the local DB so the folder is found by role
on the next operation.
Also preserves manually-set roles across IMAP syncs: if the server
doesn't return a special-use attribute for a folder that was manually
assigned a role, the local role is retained.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
