Who to follow #72

I'm picking up the roadmap item "Who to follow".

The signed API has nothing for it yet: the web gets its suggestions as an Inertia prop and dismisses them through a session route. So it comes in two parts:

1. An API PR on dev-null-sh/dev-null.sh with GET /api/v1/me/suggested-users (the web's SuggestedUsersQuery: three people, three spares, a new page each round, with why each one is suggested) and POST /api/v1/users/{username}/dismiss (Not interested). I'll link it here.
2. The app shows them in the Log after the fifth commit, as the web does on smaller screens, with Follow, Not interested, a refresh, and a way to hide them that a switch in settings brings back.