Add capability-probed structured outputs and a prototype/instance creation graph.

Probe API profiles for json_schema/tools, flatten worker artifacts onto a strict schema, and let users spawn or revise graph nodes instead of a one-shot DAG.

Co-authored-by: Cursor <cursoragent@cursor.com>

tests/parse-json-doc.test.ts

@@ -0,0 +1,31 @@
+import { describe, expect, it } from "vitest";
+import {
+  extractLastProductJson,
+  selectJsonPayload,
+  tryParseJsonDoc,
+} from "../src/parse/json-doc.js";
+
+describe("selectJsonPayload", () => {
+  it("keeps content when it is already the product", () => {
+    const json = '{"schema":"context-fragment.v1","brief":"a","正文":{}}';
+    expect(selectJsonPayload(json, "thinking...")).toBe(json);
+  });
+
+  it("falls back to reasoning when content is not JSON", () => {
+    const json = '{"schema":"context-fragment.v1","brief":"a","正文":{}}';
+    expect(selectJsonPayload("Done.", json)).toBe(json);
+  });
+});
+
+describe("extractLastProductJson", () => {
+  it("skips an earlier example object and takes the fragment", () => {
+    const raw = `example { "foo": 1 } then ${JSON.stringify({
+      schema: "context-fragment.v1",
+      brief: "点题",
+      正文: { x: 1 },
+    })}`;
+    const parsed = extractLastProductJson(raw) as { brief?: string };
+    expect(parsed?.brief).toBe("点题");
+    expect(tryParseJsonDoc(raw)).toMatchObject({ brief: "点题" });
+  });
+});