In the presentation layer, when showing branches, we'll show worktrees against branches if they're
associated. But there was a race condition: if the worktree model was refreshed after the branches model,
it wouldn't be used in the presentation layer when it came time to render the branches.
A better solution would be to have some way of signalling that a particular context needs to be refreshed
and after all the models are done being refreshed, we then refresh the contexts. This will prevent
double-renders
91909331b5