How should we design private posts?

create a plan for implementing private posts. it should specifiy how the UI should be designed, and explain the backend changes required.

my take is that a dropdown/select thing right on the left of the Post button in the composer should let the user select between Public and Private posts.

in the future, we might want to add teams, so the backend should be adaptable to that. like it's sort of a visibility: public, private, <team_id> in a way, right? or public, ? not sure what the recommendation here is.