feat(foreshadow): 写作台本章伏笔主动提醒（前端）

- 新增 chapterForeshadow 纯分类：按当前章分 可回收/待回收/已逾期（启用闲置的 isWindowApproaching）
- useChapterForeshadow hook（复用 GET /foreshadow，切章仅重分类不重拉）
- 右栏「本章参考」+ ContextDrawer 伏笔页新增「本章伏笔」实时清单，
  分色展示 + 跳看板链接 + 空态；标注『按已验收进度』

apps/web/components/workbench/ChapterAssistant.tsx

@@ -1,7 +1,9 @@
 "use client";
 
 import type { ReactNode } from "react";
+import Link from "next/link";
 import {
+  ArrowUpRight,
   Minus,
   Pin,
   PinOff,
@@ -15,6 +17,9 @@ import {
 import { ThinkingIndicator } from "@/components/ThinkingIndicator";
 import { Button } from "@/components/ui/Button";
 import { StatusNote } from "@/components/ui/StatusNote";
+import { ChapterForeshadowList } from "@/components/workbench/ChapterForeshadowList";
+import { chapterForeshadowTotal } from "@/lib/foreshadow/chapterForeshadow";
+import { useChapterForeshadow } from "@/lib/foreshadow/useChapterForeshadow";
 import { buttonClass } from "@/lib/ui/variants";
 import {
   isPinned,
@@ -183,6 +188,8 @@ export function AssistantContent({ projectId, chapterNo }: ChapterAssistantProps
         ) : null}
       </section>
 
+      <ChapterForeshadowSection projectId={projectId} chapterNo={chapterNo} />
+
       <section className="mt-6 border-t border-line-soft pt-5">
         <PanelLabel>写完后检查</PanelLabel>
         <p className="mt-1.5 text-caption leading-6 text-ink-soft">
@@ -193,6 +200,55 @@ export function AssistantContent({ projectId, chapterNo }: ChapterAssistantProps
   );
 }
 
+// 「本章伏笔」主动提醒：按当前章号把伏笔分可回收 / 待回收 / 已逾期三类，
+// 让作者在写这章时就想起该回收哪条、哪条已逾期。只读，编辑走「伏笔看板」。
+function ChapterForeshadowSection({ projectId, chapterNo }: ChapterAssistantProps) {
+  const { groups, status, reload } = useChapterForeshadow(projectId, chapterNo);
+  const boardHref = `/projects/${projectId}/foreshadow`;
+  const isEmpty = chapterForeshadowTotal(groups) === 0;
+
+  return (
+    <section className="mt-6 border-t border-line-soft pt-5">
+      <PanelLabel
+        action={<span className="text-2xs text-muted-soft">按已验收进度</span>}
+      >
+        本章伏笔
+      </PanelLabel>
+
+      {status === "loading" ? (
+        <p className="mt-2 text-caption text-ink-soft">加载伏笔…</p>
+      ) : status === "error" ? (
+        <StatusNote variant="danger" className="mt-2 text-xs" title="伏笔暂不可用">
+          <button
+            type="button"
+            onClick={reload}
+            className={buttonClass({ variant: "outline", size: "sm", className: "mt-2" })}
+          >
+            <RotateCcw className="h-3.5 w-3.5" aria-hidden="true" />
+            重试
+          </button>
+        </StatusNote>
+      ) : isEmpty ? (
+        <p className="mt-2 text-caption leading-6 text-ink-soft">
+          这一章暂无待回收或已逾期的伏笔。
+        </p>
+      ) : (
+        <div className="mt-3">
+          <ChapterForeshadowList groups={groups} />
+        </div>
+      )}
+
+      <Link
+        href={boardHref}
+        className="mt-3 inline-flex items-center gap-1 text-caption text-cinnabar hover:underline focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-cinnabar/35"
+      >
+        去伏笔看板
+        <ArrowUpRight className="h-3.5 w-3.5" aria-hidden="true" />
+      </Link>
+    </section>
+  );
+}
+
 interface EntityRowProps {
   entity: InjectionEntity;
   pinned: boolean;