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/LeftNav.tsx

@@ -3,64 +3,126 @@
 import Link from "next/link";
 import { usePathname } from "next/navigation";
 
+export type ActiveNav = "write" | "outline" | "foreshadow" | "review";
+
+interface LeftNavProps {
+  // 项目内页传 projectId → 展开项目级入口（大纲/伏笔/审稿，UX §3.1）。
+  projectId?: string;
+  activeNav?: ActiveNav;
+}
+
 interface NavItem {
   href: string;
   label: string;
-  // M1 仅作品库 + 设置可达；其余为后续里程碑占位（禁用）。
   enabled: boolean;
+  // 项目级入口的激活键（与 activeNav 比对高亮）。
+  key?: ActiveNav;
 }
 
-const NAV_ITEMS: NavItem[] = [
+const GLOBAL_ITEMS: NavItem[] = [
   { href: "/", label: "作品库", enabled: true },
   { href: "/settings/providers", label: "设置", enabled: true },
-  { href: "#outline", label: "大纲", enabled: false },
-  { href: "#codex", label: "设定库", enabled: false },
-  { href: "#foreshadow", label: "伏笔", enabled: false },
-  { href: "#review", label: "审稿", enabled: false },
-  { href: "#style", label: "文风", enabled: false },
 ];
 
-// 左导航：当前项朱砂竖条 + 浅晕底（UX §5.1）。
-export function LeftNav() {
+function projectItems(projectId: string): NavItem[] {
+  return [
+    {
+      href: `/projects/${projectId}/write`,
+      label: "写作",
+      enabled: true,
+      key: "write",
+    },
+    {
+      href: `/projects/${projectId}/outline`,
+      label: "大纲",
+      enabled: true,
+      key: "outline",
+    },
+    {
+      href: `/projects/${projectId}/foreshadow`,
+      label: "伏笔",
+      enabled: true,
+      key: "foreshadow",
+    },
+    {
+      href: `/projects/${projectId}/review`,
+      label: "审稿",
+      enabled: true,
+      key: "review",
+    },
+    { href: "#codex", label: "设定库", enabled: false },
+    { href: "#style", label: "文风", enabled: false },
+  ];
+}
+
+// 左导航：当前项朱砂竖条 + 浅晕底（UX §5.1 / §3.1）。
+export function LeftNav({ projectId, activeNav }: LeftNavProps) {
   const pathname = usePathname();
+  const scoped = projectId ? projectItems(projectId) : [];
+
   return (
     <nav
       className="w-44 shrink-0 border-r border-line bg-panel py-4"
       aria-label="主导航"
     >
       <ul className="flex flex-col gap-1 px-2">
-        {NAV_ITEMS.map((item) => {
-          const active = item.enabled && pathname === item.href;
-          if (!item.enabled) {
-            return (
-              <li key={item.label}>
-                <span
-                  className="block cursor-not-allowed rounded px-3 py-2 text-sm text-ink-soft/50"
-                  aria-disabled="true"
-                  title="后续里程碑开放"
-                >
-                  {item.label}
-                </span>
-              </li>
-            );
-          }
-          return (
-            <li key={item.label}>
-              <Link
-                href={item.href}
-                aria-current={active ? "page" : undefined}
-                className={`flex items-center gap-2 rounded px-3 py-2 text-sm ${
-                  active
-                    ? "border-l-2 border-cinnabar bg-[var(--color-cinnabar-wash)] text-cinnabar"
-                    : "text-ink hover:bg-[var(--color-cinnabar-wash)]"
-                }`}
-              >
-                {item.label}
-              </Link>
-            </li>
-          );
-        })}
+        {GLOBAL_ITEMS.map((item) => (
+          <NavLink
+            key={item.label}
+            item={item}
+            active={item.enabled && pathname === item.href}
+          />
+        ))}
+        {scoped.length > 0 ? (
+          <li
+            className="mt-3 px-3 pb-1 text-xs font-semibold uppercase tracking-wide text-ink-soft/60"
+            aria-hidden="true"
+          >
+            本作
+          </li>
+        ) : null}
+        {scoped.map((item) => (
+          <NavLink
+            key={item.label}
+            item={item}
+            active={
+              item.key !== undefined &&
+              (item.key === activeNav || pathname === item.href)
+            }
+          />
+        ))}
       </ul>
     </nav>
   );
 }
+
+function NavLink({ item, active }: { item: NavItem; active: boolean }) {
+  if (!item.enabled) {
+    return (
+      <li>
+        <span
+          className="block cursor-not-allowed rounded px-3 py-2 text-sm text-ink-soft/50"
+          aria-disabled="true"
+          title="后续里程碑开放"
+        >
+          {item.label}
+        </span>
+      </li>
+    );
+  }
+  return (
+    <li>
+      <Link
+        href={item.href}
+        aria-current={active ? "page" : undefined}
+        className={`flex items-center gap-2 rounded px-3 py-2 text-sm ${
+          active
+            ? "border-l-2 border-cinnabar bg-[var(--color-cinnabar-wash)] text-cinnabar"
+            : "text-ink hover:bg-[var(--color-cinnabar-wash)]"
+        }`}
+      >
+        {item.label}
+      </Link>
+    </li>
+  );
+}