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/api/ww_api/services/outline_context.py

@@ -0,0 +1,87 @@
+"""大纲生成的注入上下文组装（确定性序列化文本；ARCH §5.4 outliner reads / §6.2）。
+
+把 projects 设定 + 已登记伏笔 + 人物 + 世界观确定性序列化成纯文本喂给 outliner——
+**无时间戳/无 UUID**（缓存前缀稳定，不变量 #9），逐项排序保证同输入同输出（可单测）。
+outliner 据此排出分章节拍 + 伏笔回收窗口（关联本章与伏笔，§6.2）。
+
+注：reads=["projects","foreshadow","characters","world_entities"]（C6 outliner_spec），
+本组装恰好覆盖这四源，不读 digest/outline（排大纲是从设定生成、非续写既有章）。
+"""
+
+from __future__ import annotations
+
+from collections.abc import Sequence
+
+from ww_core.domain import ForeshadowLedgerView, ProjectView
+from ww_core.domain.repositories import CharacterView, WorldEntityView
+
+
+def _project_block(project: ProjectView) -> str:
+    lines = [f"标题：{project.title}"]
+    if project.genre:
+        lines.append(f"类型：{project.genre}")
+    if project.logline:
+        lines.append(f"一句话简介：{project.logline}")
+    if project.premise:
+        lines.append(f"前提：{project.premise}")
+    if project.theme:
+        lines.append(f"主题：{project.theme}")
+    if project.selling_points:
+        lines.append("卖点：" + "、".join(project.selling_points))
+    if project.structure:
+        lines.append(f"结构：{project.structure}")
+    return "【作品设定】\n" + "\n".join(lines)
+
+
+def _foreshadow_block(foreshadow: Sequence[ForeshadowLedgerView]) -> str:
+    if not foreshadow:
+        return "【已登记伏笔】\n（无）"
+    rows = sorted(foreshadow, key=lambda f: f.code)
+    lines = []
+    for f in rows:
+        window = ""
+        if f.expected_close_from is not None or f.expected_close_to is not None:
+            lo = f.expected_close_from if f.expected_close_from is not None else "?"
+            hi = f.expected_close_to if f.expected_close_to is not None else "?"
+            window = f"（回收窗口 {lo}-{hi}）"
+        plant = f"埋设第{f.planted_at}章 " if f.planted_at is not None else ""
+        lines.append(f"- [{f.code}] {f.title} {plant}{window}".rstrip())
+    return "【已登记伏笔】\n" + "\n".join(lines)
+
+
+def _characters_block(characters: Sequence[CharacterView]) -> str:
+    if not characters:
+        return "【人物】\n（无）"
+    rows = sorted(characters, key=lambda c: c.name)
+    lines = []
+    for c in rows:
+        role = f"（{c.role}）" if c.role else ""
+        motive = f" 动机：{c.motive}" if c.motive else ""
+        lines.append(f"- {c.name}{role}{motive}".rstrip())
+    return "【人物】\n" + "\n".join(lines)
+
+
+def _world_block(entities: Sequence[WorldEntityView]) -> str:
+    if not entities:
+        return "【世界观】\n（无）"
+    rows = sorted(entities, key=lambda e: (e.type, e.name))
+    lines = [f"- [{e.type}] {e.name}" for e in rows]
+    return "【世界观】\n" + "\n".join(lines)
+
+
+def build_outline_context(
+    *,
+    project: ProjectView,
+    foreshadow: Sequence[ForeshadowLedgerView],
+    characters: Sequence[CharacterView],
+    world_entities: Sequence[WorldEntityView],
+) -> str:
+    """组装 outliner 注入上下文（确定性文本，纯函数）。"""
+    return "\n\n".join(
+        [
+            _project_block(project),
+            _foreshadow_block(foreshadow),
+            _characters_block(characters),
+            _world_block(world_entities),
+        ]
+    )