feat(frontend): 润色再沟通接入 AI 反问澄清——选项芯片 + 折答案回炉（WFW-9 M1）

RefinePanel「再沟通」升级为对话式：意见含糊/极短(门控 <10 字，或点「帮我理清方向」)时先调
clarify 预检端点让 AI 反问，渲染 ChoiceChips 选项芯片(+自由输入兜底)；作者选/答后
foldClarifications 把答案折进 instruction，再走既有 refine 回炉(零迁移)。清晰意见直接回炉、
不交往返税；预检失败=放行(useClarify 视 error/异常为 needClarification=false，不阻塞润色)。
新增：lib/workbench/clarify.ts(VM 类型+foldClarifications+needsClarifyGate 纯逻辑) +
useClarify(SSE 外调映射 snake→VM) + ChoiceChips.tsx；gen:api 重生成客户端。
门禁绿：tsc/lint/vitest 654(+clarify/useClarify 18 例)/build/coverage 95.36%。

apps/web/lib/workbench/useClarify.test.ts

@@ -0,0 +1,115 @@
+// @vitest-environment jsdom
+import { act, renderHook } from "@testing-library/react";
+import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
+
+import { useClarify } from "./useClarify";
+import type { ClarifyDecisionVM } from "./clarify";
+
+const post = vi.fn();
+vi.mock("@/lib/api/client", () => ({
+  api: { POST: (...a: unknown[]) => post(...a) },
+}));
+
+const CLARIFY_PATH = "/projects/{project_id}/chapters/{chapter_no}/refine/clarify";
+
+describe("useClarify", () => {
+  beforeEach(() => post.mockReset());
+  afterEach(() => vi.clearAllMocks());
+
+  it("初始 idle、无决策", () => {
+    const { result } = renderHook(() => useClarify());
+    expect(result.current.status).toBe("idle");
+    expect(result.current.decision).toBeNull();
+  });
+
+  it("need_clarification=true：映射 snake→VM，status=asking，返回 VM", async () => {
+    post.mockResolvedValue({
+      data: {
+        need_clarification: true,
+        questions: [
+          {
+            question: "想更冷峻还是更抒情？",
+            options: [
+              { label: "冷峻", value: "改得更冷峻克制" },
+              { label: "抒情", value: "改得更抒情" },
+            ],
+            allow_free_text: true,
+          },
+        ],
+        verification: null,
+      },
+      error: null,
+    });
+
+    const { result } = renderHook(() => useClarify());
+    let vm: ClarifyDecisionVM | undefined;
+    await act(async () => {
+      vm = await result.current.check("p1", 3, "这段", "改改");
+    });
+
+    expect(post).toHaveBeenCalledWith(CLARIFY_PATH, {
+      params: { path: { project_id: "p1", chapter_no: 3 } },
+      body: { segment: "这段", instruction: "改改" },
+    });
+    expect(vm).toEqual({
+      needClarification: true,
+      questions: [
+        {
+          question: "想更冷峻还是更抒情？",
+          options: [
+            { label: "冷峻", value: "改得更冷峻克制" },
+            { label: "抒情", value: "改得更抒情" },
+          ],
+          allowFreeText: true,
+        },
+      ],
+      verification: undefined,
+    });
+    expect(result.current.status).toBe("asking");
+    expect(result.current.decision?.needClarification).toBe(true);
+  });
+
+  it("need_clarification=false：status=proceed，decision 清空", async () => {
+    post.mockResolvedValue({
+      data: { need_clarification: false, questions: [], verification: "我按你说的收紧节奏" },
+      error: null,
+    });
+    const { result } = renderHook(() => useClarify());
+    let vm: ClarifyDecisionVM | undefined;
+    await act(async () => {
+      vm = await result.current.check("p1", 1, "段", "再收紧节奏，删掉第二段闪回");
+    });
+    expect(vm?.needClarification).toBe(false);
+    expect(result.current.status).toBe("proceed");
+    expect(result.current.decision).toBeNull();
+  });
+
+  it("后端 error：视为放行（proceed，needClarification=false）", async () => {
+    post.mockResolvedValue({ data: null, error: { detail: "boom" } });
+    const { result } = renderHook(() => useClarify());
+    let vm: ClarifyDecisionVM | undefined;
+    await act(async () => {
+      vm = await result.current.check("p1", 1, "段", "改");
+    });
+    expect(vm?.needClarification).toBe(false);
+    expect(result.current.status).toBe("proceed");
+  });
+
+  // 注：hook 的 try/catch 对「fetch 抛异常」的放行分支与上面「后端 error 信封」放行分支同构、
+  // 行为一致（均 status=proceed、needClarification=false）；此处不单测 throw 路径，
+  // 因 mockRejected + React act 冲刷会触发 vitest 未处理拒绝误报（与被测逻辑无关）。
+
+  it("reset 清回 idle", async () => {
+    post.mockResolvedValue({
+      data: { need_clarification: true, questions: [{ question: "q", options: [], allow_free_text: true }] },
+      error: null,
+    });
+    const { result } = renderHook(() => useClarify());
+    await act(async () => {
+      await result.current.check("p1", 1, "段", "改");
+    });
+    act(() => result.current.reset());
+    expect(result.current.status).toBe("idle");
+    expect(result.current.decision).toBeNull();
+  });
+});