Press Enter while busy with a draft to queue it; with no draft to interrupt
and send the next queued turn. Auto-drains one queued turn each time the
session settles, same as Cursor. Queue persists across reloads so an
interrupted-and-queued turn isn't lost on refresh.
Each queued row supports edit-in-composer (with explicit Save/Cancel),
send-now (↑), and delete. Drain skips only the entry currently being
edited so the rest of the queue keeps flowing.
Queue dequeue is transactional — an entry only leaves the queue after
`prompt.submit` is accepted, so a rejected submit doesn't drop the turn.
Also shrinks the `[interrupted]` marker to a muted one-liner and drops
its assistant footer so it stops looking like a real reply.