feat: M3 — 伏笔账本 + 节奏引擎 + 大纲（含并发记账 bugfix）

- 伏笔账本：纯函数状态机(OPEN/PARTIAL/CLOSED/OVERDUE) + ForeshadowLedger repo；验收后到期扫描(BackgroundTask 自建 session 置 OVERDUE)；登记/状态变更端点
- 节奏 + 三审齐：foreshadow-analyst + pace-checker 并入 LangGraph 并行审(REVIEW_SPECS)，collect 分列落 chapter_reviews(conflicts/foreshadow_sug/pace)，review SSE 加 foreshadow/pace 事件
- 大纲：outliner Agent 产 OutlineResult(含 foreshadow_windows)，POST /outline 逐章 upsert outline 表；GET /foreshadow?status= 看板
- 前端：伏笔四泳道看板(OVERDUE 琥珀) + 大纲编辑器(窗口徽标) + 节奏节拍图(▁▃▅) + 审稿页消费 foreshadow/pace SSE
- bugfix(T3.8)：并行三审共用请求 session 记账触发 'Session is already flushing' → foreshadow/pace 静默丢失；SqlAlchemyLedgerSink.record 改 add-only(靠端点/事务 commit)，加并发回归测试
- M3 E2E：真实 DB + mock 网关零 token 走通 埋设→进展→验收后扫描 OVERDUE→看板 + 大纲含窗口 + 三审齐 SSE/留痕；E2E 暴露并钉住上述 bug
- 门禁绿：mypy 111 / pytest 228(0 xfailed) / alembic 无漂移；前端 gen:api/lint/tsc/vitest 69/build

apps/web/components/outline/OutlineChapterRow.tsx

@@ -0,0 +1,51 @@
+"use client";
+
+import type { OutlineChapterView } from "@/lib/api/types";
+import {
+  isCloseWindow,
+  windowBadgeLabel,
+} from "@/lib/outline/outline";
+
+interface OutlineChapterRowProps {
+  chapter: OutlineChapterView;
+}
+
+// 单章大纲行（UX §6.7）：章号 + beats + 伏笔窗口徽标（⚑）。
+// 接近回收窗口的徽标用琥珀 + 「可回收」提示（a11y：图标 + 文案，不单靠色）。
+export function OutlineChapterRow({ chapter }: OutlineChapterRowProps) {
+  const windows = chapter.foreshadow_windows ?? [];
+  return (
+    <li className="border-l-2 border-line py-2 pl-3">
+      <div className="flex flex-wrap items-center gap-2">
+        <span className="font-mono text-xs text-ink-soft">
+          第 {chapter.no} 章
+        </span>
+        {windows.map((w) => {
+          const close = isCloseWindow(chapter, w);
+          return (
+            <span
+              key={w.code}
+              title={close ? "进入回收窗口，建议本章安排回收" : undefined}
+              className={`rounded px-1.5 py-0.5 text-xs ${
+                close
+                  ? "bg-overdue/15 text-overdue"
+                  : "bg-[var(--color-cinnabar-wash)] text-cinnabar"
+              }`}
+            >
+              {windowBadgeLabel(w)}
+              {close ? " · 可回收" : ""}
+            </span>
+          );
+        })}
+      </div>
+      {chapter.beats && chapter.beats.length > 0 ? (
+        <p className="mt-1 text-sm text-ink">
+          <span className="text-ink-soft">beats: </span>
+          {chapter.beats.join(" / ")}
+        </p>
+      ) : (
+        <p className="mt-1 text-sm text-ink-soft/60">（无节拍）</p>
+      )}
+    </li>
+  );
+}

apps/web/components/outline/OutlineEditor.tsx

@@ -0,0 +1,97 @@
+"use client";
+
+import { useMemo, useState } from "react";
+
+import { AppShell } from "@/components/AppShell";
+import type { OutlineChapterView, ProjectResponse } from "@/lib/api/types";
+import { groupByVolume } from "@/lib/outline/outline";
+import { useOutline } from "@/lib/outline/useOutline";
+import { OutlineChapterRow } from "./OutlineChapterRow";
+
+interface OutlineEditorProps {
+  project: ProjectResponse;
+  initialChapters: OutlineChapterView[];
+}
+
+// 大纲编辑器主体（UX §6.7）。RSC 种入已存大纲；Client 承载生成（POST .../outline）。
+// 无凭据 → 503 LLM_UNAVAILABLE 经 error 检出、引导去设置。
+export function OutlineEditor({
+  project,
+  initialChapters,
+}: OutlineEditorProps) {
+  const { chapters, status, error, generate } = useOutline(initialChapters);
+  const [volume, setVolume] = useState(1);
+  const volumes = useMemo(() => groupByVolume(chapters), [chapters]);
+  const generating = status === "generating";
+
+  return (
+    <AppShell
+      title={`〈${project.title}〉`}
+      subtitle="大纲"
+      projectId={project.id}
+      activeNav="outline"
+    >
+      <div className="flex h-[calc(100vh-4rem)] flex-col p-6">
+        <div className="mb-4 flex items-center gap-3">
+          <h1 className="font-serif text-lg text-ink">大纲</h1>
+          <label htmlFor="vol" className="ml-auto text-xs text-ink-soft">
+            卷号
+          </label>
+          <input
+            id="vol"
+            inputMode="numeric"
+            value={volume}
+            onChange={(e) => setVolume(Math.max(1, Number(e.target.value) || 1))}
+            className="w-16 rounded border border-line bg-bg px-2 py-1 text-sm text-ink focus:border-cinnabar focus:outline-none"
+          />
+          <button
+            type="button"
+            disabled={generating}
+            onClick={() => void generate(project.id, volume)}
+            className="rounded bg-cinnabar px-3 py-1.5 text-sm text-panel hover:opacity-90 disabled:opacity-40"
+          >
+            {generating ? "排大纲中…" : "✦ AI 排大纲"}
+          </button>
+        </div>
+
+        {error ? (
+          <p className="mb-4 text-sm text-conflict">
+            大纲生成失败（{error.code}）：{error.message}
+            {error.code === "LLM_UNAVAILABLE" ? (
+              <>
+                {" "}
+                <a
+                  href="/settings/providers"
+                  className="underline hover:text-cinnabar"
+                >
+                  去设置提供商
+                </a>
+              </>
+            ) : null}
+          </p>
+        ) : null}
+
+        <div className="min-h-0 flex-1 overflow-auto">
+          {volumes.length === 0 ? (
+            <p className="rounded border border-dashed border-line p-6 text-sm text-ink-soft">
+              暂无大纲。点「✦ AI 排大纲」生成逐章节拍与伏笔窗口。
+            </p>
+          ) : (
+            volumes.map((group) => (
+              <section key={group.volume} className="mb-6">
+                <h2 className="mb-2 font-serif text-base text-ink">
+                  卷 {group.volume}
+                </h2>
+                <ul className="space-y-1">
+                  {group.chapters.map((ch) => (
+                    <OutlineChapterRow key={ch.no} chapter={ch} />
+                  ))}
+                </ul>
+              </section>
+            ))
+          )}
+        </div>
+      </div>
+    </AppShell>
+  );
+}