Filter "no snippets" users to the bottom of list / collapse

Snippets are not required, so some people are not going to write them. All the "no snippets" users add unnecessary visual noise to the list that makes it harder to read, so filter all to the bottom of list (and potentially collapse their visual display to be a more condensed list of those people).

Start by locating the code that builds and renders the user list, then trace how users without snippets are represented. Implement bottom placement and assess whether a condensed display fits the existing list structure; done means users with snippets remain readable while users without snippets no longer add the same visual noise.

Written by the indexing model from the issue text.