Wave 0: shared contracts + extension points

- src/core/contracts.ts: plan tree / graph / ledger / job protocol / artifact
  registry types — the single source of truth for all workstreams
- tools: per-request factory createTeacherTools({chatId}) composing
  questionTools + planTools (stub) + jobTools (stub); quiz gains nodeId
- prompt composition: system-prompt.md + sorted src/agent/prompts/*.md
- ChatRecord.tree + saveTree; pending gate scoped to quiz/ask (+findPendingJobCall)
- chat.tsx: artifact renderer extension point + ChatActionsContext.syncFromServer

src/core/pending.ts

@@ -1,9 +1,13 @@
 import { isToolUIPart, type UIMessage } from "ai";
 
 /**
- * The pending-question gate: an unanswered interaction tool part (quiz/ask)
+ * The pending-question gate: an unanswered QUESTION tool part (quiz/ask)
  * blocks the composer — one question at a time, mirroring the teacher's
  * prompt contract. Derived client state; the server enforces nothing.
+ *
+ * Job tool parts (research/demo/visual) are NOT returned here — they gate
+ * sending separately with a "waiting for <job>" affordance (see contracts.ts
+ * "THE ASYNC PROTOCOL" §5; use findPendingJobCall).
  */
 export interface PendingToolCall {
 	toolCallId: string;
@@ -12,15 +16,33 @@ export interface PendingToolCall {
 	input: unknown;
 }
 
-export function findPendingToolCall(messages: UIMessage[]): PendingToolCall | null {
+/** Tools that render in the question dock and gate the composer. */
+export const QUESTION_TOOLS = ["quiz", "ask_user_question"] as const;
+
+/** Tools fulfilled by background sub-agent jobs (W2/W6). */
+export const JOB_TOOLS = ["research", "demo", "visual"] as const;
+
+function findPending(messages: UIMessage[], names: readonly string[]): PendingToolCall | null {
 	for (let m = messages.length - 1; m >= 0; m--) {
 		const msg = messages[m]!;
 		for (let p = msg.parts.length - 1; p >= 0; p--) {
 			const part = msg.parts[p]!;
 			if (isToolUIPart(part) && part.state === "input-available") {
-				return { toolCallId: part.toolCallId, tool: part.type.slice("tool-".length), input: part.input };
+				const tool = part.type.slice("tool-".length);
+				if (names.includes(tool)) {
+					return { toolCallId: part.toolCallId, tool, input: part.input };
+				}
 			}
 		}
 	}
 	return null;
 }
+
+export function findPendingToolCall(messages: UIMessage[]): PendingToolCall | null {
+	return findPending(messages, QUESTION_TOOLS);
+}
+
+/** The running background job, if any (input-available research/demo/visual part). */
+export function findPendingJobCall(messages: UIMessage[]): PendingToolCall | null {
+	return findPending(messages, JOB_TOOLS);
+}