With continuation coalescing, a job flips done at CLAIM time — while the
learner's own answer turn is still streaming. The poller's settle re-sync
fired on the flip, swapping in a mid-turn record snapshot mid-stream; the
steer after the assistant message broke the SDK's in-place continuation
merge, and the streaming response landed as a SECOND message with the same
id — duplicate React keys in the live transcript (the user's live test hit
it; the record itself stayed clean).
A settle during a busy turn (local stream OR server turnInFlight) now marks
a pending sync; the first idle poll tick adopts the finished record. This
also fixes the latent multi-job race: steer B settling while steer A's wake
turn is in flight would have grabbed the same mid-turn snapshot.
Out-of-lane surgical touch (flagged for master review): the wave-1 poller
block in components/chat.tsx.