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

packages/agents/ww_agents/__init__.py

@@ -1,17 +1,44 @@
 """ww-agents：内置 Agent 声明（AgentSpec）+ 结构化输出 schema（C6）。
 
-对齐 ARCH §5.1（AgentSpec）/ §5.4（I/O 契约）/ §6.1（冲突分类）。
+对齐 ARCH §5.1（AgentSpec）/ §5.4（I/O 契约）/ §6.1（冲突分类）/ §6.2 §6.4（伏笔/节奏）。
 """
 
 from __future__ import annotations
 
-from .schemas import Conflict, ConflictType, ContinuityReview
-from .specs import AgentSpec, continuity_spec
+from .schemas import (
+    Conflict,
+    ConflictType,
+    ContinuityReview,
+    ForeshadowReview,
+    ForeshadowSuggestion,
+    ForeshadowWindow,
+    OutlineChapter,
+    OutlineResult,
+    PaceIssue,
+    PaceReview,
+)
+from .specs import (
+    AgentSpec,
+    continuity_spec,
+    foreshadow_spec,
+    outliner_spec,
+    pace_spec,
+)
 
 __all__ = [
     "AgentSpec",
     "Conflict",
     "ConflictType",
     "ContinuityReview",
+    "ForeshadowReview",
+    "ForeshadowSuggestion",
+    "ForeshadowWindow",
+    "OutlineChapter",
+    "OutlineResult",
+    "PaceIssue",
+    "PaceReview",
     "continuity_spec",
+    "foreshadow_spec",
+    "outliner_spec",
+    "pace_spec",
 ]