Lift the queue subsystem out of ChatBar into composer/hooks/use-composer-queue.ts:
the per-session queue-store binding + queuedPrompts, in-place queued-prompt
editing (begin/step/exit), the shared drain lock + send-then-remove sequence,
manual send-now, bounded auto-drain, and the three queue effects (re-key migrate,
idle auto-drain, queue-edit cleanup).
It consumes the draft API (draftRef/clearDraft/loadIntoComposer/focusInput) and
writes the coordinator-owned `queueEditRef` the draft engine reads — so the
draft↔queue coupling is two explicit deps, not an inline tangle. `steerDraft`
and the chat-focus Esc-cancel stay in ChatBar (not queue-internal).
Behaviour-identical (verbatim move). Verified: typecheck clean, composer DOM
repro tests + queue/edit paths pass.
4c4b790f11