Dex for Teams: Sync changes from personal to workspace in Dex

When I copy a contact from my personal Dex into a team space and choose which fields to share (like email addresses), later changes to those fields on my personal contact don't reach the team copy. I have to update both by hand.

Request: keep the shared fields synced from the personal contact to the team copy, the way groups sync already works. If a teammate edited that field on the team copy, their edit wins. New values like an extra email get added, not replaced. Unlinking stops the sync without erasing anything.