Merge main: wave-4 backend (activity abort endpoint, lastStep capture)

app/api/activity/abort/route.ts

@@ -0,0 +1,42 @@
+/**
+ * POST /api/activity/abort — the dock's END/ABORT control, uniform across
+ * process kinds (user-decided contract): body {kind: "job"|"extraction", id}
+ * where id is the jobId for sub-agent jobs and the chatId for extraction
+ * runs (the pipeline registry is chat-keyed). Mechanisms live in their
+ * domains — abortJob (server/jobs.ts, agents stream) and abortExtraction
+ * (the pipeline module, graph stream); this route is the thin composition.
+ *
+ * Outcomes: a job's not_found -> 404, not_running -> 409, aborted -> 200.
+ * Extraction abort is idempotent by design (aborting with nothing in
+ * flight is success — the blob is gone either way) -> 200.
+ */
+import { abortExtraction, abortJob } from "@/src/server";
+
+export async function POST(req: Request) {
+	let body: unknown;
+	try {
+		body = await req.json();
+	} catch {
+		return Response.json({ error: "Invalid JSON body" }, { status: 400 });
+	}
+	const { kind, id } = (body ?? {}) as { kind?: string; id?: string };
+	if ((kind !== "job" && kind !== "extraction") || typeof id !== "string" || id === "") {
+		return Response.json({ error: 'Body must be {kind: "job"|"extraction", id: string}' }, { status: 400 });
+	}
+	if (!/^[A-Za-z0-9_-]+$/.test(id)) {
+		return Response.json({ error: "Invalid id" }, { status: 400 });
+	}
+
+	if (kind === "job") {
+		const outcome = abortJob(id);
+		if (!outcome.ok) {
+			const status = outcome.reason === "not_found" ? 404 : 409;
+			return Response.json({ ok: false, reason: outcome.reason }, { status });
+		}
+		return Response.json({ ok: true });
+	}
+	// kind === "extraction": true cancellation; idempotent (nothing in
+	// flight is success — same dock outcome)
+	abortExtraction(id);
+	return Response.json({ ok: true });
+}

app/api/graph/status/route.ts

@@ -15,6 +15,10 @@ export async function GET() {
 		title: chatStore.getChat(run.chatId)?.title ?? run.chatId,
 		phase: run.phase,
 		startedAt: run.startedAt,
+		// Live per-stage usage (the money channel): model + per-step CallUsage,
+		// accumulated as steps bill. Cost and context-window folds are the
+		// consumer's (core/prices.ts helpers — nothing stores dollars).
+		usage: run.usage,
 	}));
 	return Response.json({ runs });
 }