Completes the 'Talk to AIUI about it' path from the other side. archyBridge
gains a chat:prefill case behind its existing parent-origin validation, and
ChatInput prefills + focuses with the caret at the end.
Prefills rather than auto-sends: the operator sees and can amend the question
before it costs a model call, and a draft they had already started is never
clobbered by a background handoff. Auto-send is the natural seam for the
follow-up that actions things directly.
The bridge buffers a prefill that arrives before the composer mounts (collapsed
chat, mobile content tab) and replays it on registration, so a Cmd+K ask into a
cold frame is not silently dropped. onPrefill returns an unsubscribe so a
remounting composer cannot leak a stale handler.
Verified: vue-tsc clean; AIUI suite 332 passed. The 3 remaining failures
(seed-songs extraction x2, web-search system prompt) are pre-existing — I
confirmed by reverting 13-01's two AIUI files to their parent state and
reproducing the identical 3 failures without any phase-13 change present.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
