Looks good aside from the non-blocking comments.
This doesn't belong in this patch I think.
Perhaps a Resource should become a SharedFolder (via inheritance directly, or perhaps via a baseclass to avoid including the wrong traits),? Otherwise we just duplicate code.
From manual testing it seems to me that a new shared folder never makes it out of the "Not Ready" state.
The controller is repeatedly queried for a status update, but the code never checks back in imap/ldap after initially failing on a GETMETADATA command (when creating the folder).
The only way to get it active is to wait for a Refresh button to appear (after a pretty long timeout), pressing it immediately turns it to active.
Could be that it fixes itself when waiting for longer, but from a UX perspective it's not ideal (but perhaps just a later enhancement).