When merging accounts with different Names, allow defining which Name should survive

In Hatstall, when I merge two or three accounts, I have no influence which "Name" entry will survive. That means I often have to edit the (now-merged) account name again after merging.

It seems that the last Name in the results list is always taken as the new Name for the merged accounts.

Start by tracing Hatstall's account-merging flow and the results list mentioned in the issue. Determine how the surviving Name is selected and where a user could choose it before merging. Done means the chosen Name survives when two or three accounts are merged, without requiring a later edit.

Written by the indexing model from the issue text.