Merge feat/sub-agents: author-once plan protocol, steer-delivery starvation fixes, research-steer affordance

Wave 3: the plan protocol collapses to one re-callable mermaid plan_init
(seven mutation tools deleted by design; statuses derive from quiz checks;
live quiz-nodeId validation with mid-turn retry). The steer-starvation arc:
steers deliver coalesced with the learner's answer (claimSteers), persist
dedupes same-id continuation copies, jobs settle-sync defers while a turn
is busy. Research steers gain the collapsed full-brief affordance. Model
reasoning effort set to minimal across roles.

components/artifacts/steer-card.tsx

@@ -15,11 +15,11 @@ import { VisualOutputCard } from "@/components/artifacts/visual-card";
  * ("data-subagent-artifact") carries the result. It renders as an artifact —
  * NEVER a learner bubble, never wrapped in a message container:
  *
- *   research — a quiet "Research complete" badge. The full brief is TOO LONG
- *     to inline and the teacher's wake turn weaves it into the lesson anyway;
- *     it stays persisted in the transcript (the artifact part), so a
- *     "view full research" affordance can be added later. Failures keep the
- *     failure card (the brief explains what went wrong).
+ *   research — a quiet "Research complete" one-liner that expands on demand
+ *     (native <details>) to the full persisted brief + sources: the brief is
+ *     too long to inline by default and the teacher's wake turn weaves it
+ *     into the lesson anyway. Failures keep the failure card (the brief
+ *     explains what went wrong).
  *   demo / visual — the artifact itself (sandboxed iframe / sanitized SVG).
  *     The sub-agent's verification notes are model-facing glue and do NOT
  *     render; only a failure note does.
@@ -48,15 +48,25 @@ export function SubagentSteerCard({ message }: { message: TeacherUIMessage }) {
 	}
 }
 
-/** Quiet one-liner, the dispatch-settled idiom: the brief lives in the record,
- * the lesson lives in the teacher's wake turn — the badge just marks delivery. */
+/** Quiet one-liner, the dispatch-settled idiom — the lesson lives in the
+ * teacher's wake turn; the badge just marks delivery. The persisted brief
+ * rides along in a collapsed <details> (the wave-1 "view full research"
+ * affordance): full markdown + sources, one click away, no extra fetch —
+ * the artifact part in the record is the single source of truth. */
 function ResearchCompleteBadge({ result }: { result: ResearchResult }) {
 	return (
-		<div className="flex items-center gap-2 text-xs text-muted-foreground" data-testid="research-complete-badge">
-			<CheckIcon className="size-3.5" />
-			<span className="font-medium uppercase tracking-wide">Research</span>
-			<span>complete</span>
-			{result.sources.length > 0 && <span>· {result.sources.length} sources</span>}
-		</div>
+		<details data-testid="research-complete-badge" className="group w-full text-xs text-muted-foreground">
+			<summary className="flex cursor-pointer select-none list-none items-center gap-2 [&::-webkit-details-marker]:hidden">
+				<CheckIcon className="size-3.5" />
+				<span className="font-medium uppercase tracking-wide">Research</span>
+				<span>complete</span>
+				{result.sources.length > 0 && <span>· {result.sources.length} sources</span>}
+				<span className="ml-1 text-[11px] text-muted-foreground/70 group-open:hidden">view brief</span>
+				<span className="ml-1 hidden text-[11px] text-muted-foreground/70 group-open:inline">hide brief</span>
+			</summary>
+			<div className="mt-2">
+				<ResearchBriefCard output={result} />
+			</div>
+		</details>
 	);
 }

components/chat.tsx

@@ -178,11 +178,15 @@ export function Chat({
 	// ── Central job observability (contracts.ts "THE ASYNC PROTOCOL" §4) ──
 	// ONE poll of /api/jobs drives every job surface (transcript dispatch
 	// cards, the sub-agents panel) and re-syncs the transcript exactly once
-	// when a job settles: job status flips done/error only AFTER the wake
-	// turn's messages are persisted, so a completion means the record already
-	// holds the steer + the teacher's response — one syncFromServer adopts it
-	// all. Poll fast while jobs run, slow otherwise (new-dispatch discovery),
-	// and not at all when this session has never dispatched a job.
+	// when a job settles. A settle no longer implies the record is complete:
+	// CONTINUATION COALESCING flips the job done at claim time — while the
+	// learner's own answer turn is still streaming (and a settle can race a
+	// second job's wake turn). Syncing mid-turn would swap in a stale snapshot
+	// mid-stream, which breaks the SDK's in-place continuation merge (duplicate
+	// message ids). So: a settle during a busy turn defers the sync; the next
+	// idle poll tick adopts the finished record. Poll fast while jobs run,
+	// slow otherwise (new-dispatch discovery), and not at all when this
+	// session has never dispatched a job.
 	const [jobs, setJobs] = useState<JobRecord[]>([]);
 	const jobPartCount = useMemo(
 		() =>
@@ -201,6 +205,8 @@ export function Chat({
 	const localStreamRef = useRef(false);
 	localStreamRef.current = localStream;
 	const jobStatusRef = useRef<Map<string, string>>(new Map());
+	// A settle seen during a busy turn — the sync is owed, not dropped.
+	const pendingSyncRef = useRef(false);
 	useEffect(() => {
 		if (pollMs === 0) return;
 		let cancelled = false;
@@ -214,9 +220,26 @@ export function Chat({
 				const list = data.jobs ?? [];
 				for (const j of list) {
 					const prev = jobStatusRef.current.get(j.id);
-					if (prev === "running" && j.status !== "running") void syncFromServer();
+					if (prev === "running" && j.status !== "running") {
+						// The record is only guaranteed complete when no turn is in
+					// flight — locally or server-side. A coalesced settle fires
+					// mid-turn by design; adopt the record on the first idle tick.
+						if (localStreamRef.current || data.turnInFlight === true) {
+							pendingSyncRef.current = true;
+						} else {
+							void syncFromServer();
+					}
+				}
 					jobStatusRef.current.set(j.id, j.status);
 				}
+				if (
+					pendingSyncRef.current &&
+					!localStreamRef.current &&
+					data.turnInFlight !== true
+				) {
+					pendingSyncRef.current = false;
+					void syncFromServer();
+				}
 				setJobs(list);
 				// Wake-turn adoption: a server-side teacher turn with no client request
 				// of ours (sub-agent delivery) — the same machinery as returning