feat(review): 审稿选章可用——列章端点 + 选章下拉全章可见 + 默认最近章

- 后端新增 GET /projects/{id}/chapters（列真实存在的章 + has_draft/accepted/reviewed_at），TDD 10 测
- gen:api 重生成 TS 客户端（ChapterListItem）
- 选章下拉去掉 hidden（手机/窄屏也可切章）；选项以真实章为准 + 大纲结构，
  无草稿章置灰（仅当前章例外），覆盖『写过但不在大纲』的章
- 无 ?chapter 时默认落到最近一个有草稿的章，而非硬编码第 1 章

apps/api/ww_api/services/chapter_list.py

@@ -0,0 +1,109 @@
+"""列章只读服务：枚举项目「真实存在的章」+ 可审/已审标记（审稿选章下拉用）。
+
+数据来源：`chapters`（草稿/accepted 版本）+ `chapter_reviews`。核心业务逻辑是把这两张表
+的行**聚合**为「按章号去重、升序」的列章视图，抽成纯函数 `build_chapter_list` 以便脱库直测
+（真 PG 行为交 tests/ E2E，符合本仓单测确定性纪律）。`SqlChapterLister` 只负责取行 + 调聚合。
+
+不变量：只读、不写库、不触 LLM；按 project_id 隔离（owner 校验在端点走 project_repo，同其它端点）。
+"""
+
+from __future__ import annotations
+
+import uuid
+from dataclasses import dataclass
+from datetime import datetime
+from typing import Protocol
+
+from sqlalchemy import select
+from sqlalchemy.ext.asyncio import AsyncSession
+from ww_core.domain.chapter_repo import ACCEPTED_STATUS, DRAFT_STATUS
+from ww_db.models import Chapter, ChapterReview
+
+from ww_api.schemas.projects import ChapterListItem
+
+
+@dataclass(frozen=True)
+class ChapterRow:
+    """`chapters` 行的最小读投影（聚合所需字段）。"""
+
+    chapter_no: int
+    status: str
+    content: str | None
+
+
+@dataclass(frozen=True)
+class ReviewRow:
+    """`chapter_reviews` 行的最小读投影（章号 + 审稿时间）。"""
+
+    chapter_no: int
+    created_at: datetime
+
+
+def build_chapter_list(
+    chapter_rows: list[ChapterRow], review_rows: list[ReviewRow]
+) -> list[ChapterListItem]:
+    """把 chapters/reviews 行聚合为按章号去重、升序的列章视图（纯函数，无副作用）。
+
+    - `has_draft`：该章存在 status='draft' 且正文非空白的行（与 GET .../draft「空草稿=无」一致）。
+    - `accepted`：该章存在 status='accepted' 行。
+    - `reviewed_at`：该章审稿行 created_at 的最大值（无审稿则 None）。
+    - 章号来自两表并集（含仅审稿未存草稿的章），去重后升序。
+    """
+    has_draft: dict[int, bool] = {}
+    accepted: dict[int, bool] = {}
+    reviewed_at: dict[int, datetime] = {}
+
+    for row in chapter_rows:
+        if row.status == DRAFT_STATUS and row.content is not None and row.content.strip():
+            has_draft[row.chapter_no] = True
+        if row.status == ACCEPTED_STATUS:
+            accepted[row.chapter_no] = True
+
+    for review in review_rows:
+        current = reviewed_at.get(review.chapter_no)
+        if current is None or review.created_at > current:
+            reviewed_at[review.chapter_no] = review.created_at
+
+    chapter_nos = sorted({r.chapter_no for r in chapter_rows} | {r.chapter_no for r in review_rows})
+    return [
+        ChapterListItem(
+            chapter_no=no,
+            has_draft=has_draft.get(no, False),
+            accepted=accepted.get(no, False),
+            reviewed_at=reviewed_at.get(no),
+        )
+        for no in chapter_nos
+    ]
+
+
+class ChapterLister(Protocol):
+    """列章只读接口（按 project_id 隔离）——端点依赖此协议，测试可注入 fake。"""
+
+    async def list_chapters(self, project_id: uuid.UUID) -> list[ChapterListItem]: ...
+
+
+class SqlChapterLister:
+    """SQLAlchemy 实现：两条只读查询取行 → 交纯聚合。单项目章数有界，聚合放 Python 侧（KISS）。"""
+
+    def __init__(self, session: AsyncSession) -> None:
+        self._s = session
+
+    async def list_chapters(self, project_id: uuid.UUID) -> list[ChapterListItem]:
+        chapter_result = await self._s.execute(
+            select(Chapter.chapter_no, Chapter.status, Chapter.content).where(
+                Chapter.project_id == project_id
+            )
+        )
+        review_result = await self._s.execute(
+            select(ChapterReview.chapter_no, ChapterReview.created_at).where(
+                ChapterReview.project_id == project_id
+            )
+        )
+        chapter_rows = [
+            ChapterRow(chapter_no=r.chapter_no, status=r.status, content=r.content)
+            for r in chapter_result.all()
+        ]
+        review_rows = [
+            ReviewRow(chapter_no=r.chapter_no, created_at=r.created_at) for r in review_result.all()
+        ]
+        return build_chapter_list(chapter_rows, review_rows)

apps/api/ww_api/services/project_deps.py

@@ -53,6 +53,7 @@ from ww_api.security.credentials import (
     CredentialKeyError,
     decrypt_api_key,
 )
+from ww_api.services.chapter_list import ChapterLister, SqlChapterLister
 from ww_api.services.credentials import (
     AUTH_TYPE_OAUTH,
     STUB_OWNER_ID,
@@ -99,6 +100,13 @@ def get_chapter_repo(
     return SqlChapterRepo(session)
 
 
+def get_chapter_lister(
+    session: Annotated[AsyncSession, Depends(get_session)],
+) -> ChapterLister:
+    """列章只读服务（GET /projects/:id/chapters）。只读、不写库；测试注入 fake lister。"""
+    return SqlChapterLister(session)
+
+
 def get_memory_repos(
     session: Annotated[AsyncSession, Depends(get_session)],
 ) -> MemoryRepos: