search: better name detection for accounts

[prohr]

Searching by name for existing accounts only works if people explicitly put it in their display name.

These "first last" queries should also match against the following variants in both the display name + the handle:

first.last firstlast

For examples of several accounts which currently fit this pattern, scroll upthread here:

https://bsky.app/profile/bnewbold.net/post/3l2np6wbnpu22