pub fn refresh_mailbox<M: MailboxSource>(app: &mut App, mailbox_source: &M)Expand description
Mailbox-only refresh — extracted so PR-UI-4+ can call it on its
own cadence (e.g. in response to a broker INSERT signal) without
re-running the heavier compose + tmux capture path. PR-UI-3
just calls it from the main refresh once per tick.