feat(frontend): 整章重写接入 AI 反问澄清——useRewriteClarify + ChapterRewritePanel 门控（WFW-9 M2）

apps/web/lib/workbench/useRewriteClarify.ts

@@ -0,0 +1,70 @@
+"use client";
+
+import { useCallback, useState } from "react";
+
+import { api } from "@/lib/api/client";
+import { PROCEED, toVM, type ClarifyDecisionVM } from "./clarify";
+
+export type ClarifyStatus = "idle" | "checking" | "asking" | "proceed" | "error";
+
+export interface UseRewriteClarify {
+  status: ClarifyStatus;
+  // status=asking 时的待答问题（含选项）；其它时为 null。
+  decision: ClarifyDecisionVM | null;
+  // 预检：调 rewrite/clarify 端点，返回 VM 供调用方同步分支。失败=放行（needClarification=false），不阻塞整章重写。
+  check: (
+    projectId: string,
+    chapterNo: number,
+    feedback: string,
+    priorDraft: string,
+  ) => Promise<ClarifyDecisionVM>;
+  reset: () => void;
+}
+
+// 整章重写侧 AI 反问澄清预检（WFW-9 M2，路线A 两阶段之「问题」阶段——refine/clarify 的章级孪生）。
+// 「再沟通/重写」意见含糊/极短时先调独立非流式端点让 AI 反问；needClarification=false 或失败=放行去既有 rewrite SSE。
+export function useRewriteClarify(): UseRewriteClarify {
+  const [status, setStatus] = useState<ClarifyStatus>("idle");
+  const [decision, setDecision] = useState<ClarifyDecisionVM | null>(null);
+
+  const check = useCallback<UseRewriteClarify["check"]>(
+    async (projectId, chapterNo, feedback, priorDraft) => {
+      setStatus("checking");
+      try {
+        const { data, error } = await api.POST(
+          "/projects/{project_id}/chapters/{chapter_no}/rewrite/clarify",
+          {
+            params: { path: { project_id: projectId, chapter_no: chapterNo } },
+            body: { feedback, prior_draft: priorDraft },
+          },
+        );
+        if (error || !data) {
+          setStatus("proceed");
+          setDecision(null);
+          return PROCEED;
+        }
+        const vm = toVM(data);
+        if (vm.needClarification && vm.questions.length > 0) {
+          setStatus("asking");
+          setDecision(vm);
+        } else {
+          setStatus("proceed");
+          setDecision(null);
+        }
+        return vm;
+      } catch {
+        setStatus("proceed");
+        setDecision(null);
+        return PROCEED;
+      }
+    },
+    [],
+  );
+
+  const reset = useCallback((): void => {
+    setStatus("idle");
+    setDecision(null);
+  }, []);
+
+  return { status, decision, check, reset };
+}