The wake pump fires its turn with the steer INSIDE the request body but
dequeues the queue entry only after the turn returns 200 — so the entry
is still queued when the handler claims. The record doesn't carry the
steer yet (write-ahead persist hasn't run), so claimSteers claimed it a
SECOND time and the handler appended it: outgoing = [...body, ...claimed]
held two copies of the same deterministic steer id, and the write-ahead
persist saved that for the whole wake turn. The client's adoption poll
rendered both -> React duplicate-key warning (steer_ctx_<chatId>).
withMessageIds deduped only at onFinish, so the final record looked clean.
Fix: claimSteers(chatId, incoming) — a queued steer whose id is already in
the turn's incoming list is being delivered BY this very turn: finalized
and resolved, never appended again.