feat(review): 医生核对包入口；CEUS 运行目录的读取收进 runs

- 新模块 review（组织层，只依赖 library、answers、runs）：把一次构建和它装入的
  CEUS 运行整理成医生可读的文件夹（CSV 带 BOM、说明与报告转 PDF、图片视频逐字节拷贝），
  入口 scripts/review_pack.py + config/review_pack.yaml。任务书 03。
- 读 CEUS 运行目录（failed.csv、结果目录、关键帧文件）从 build 挪进 runs，build 与
  review 都经它读；failed.csv 读取在边界上收严（步号须为整数、视频号不重复、列数固定）。
- library、answers 补只读函数；import-linter 增 review 契约。
- 文档：guides/医生核对包.md（过一轮硕士生阅读），结构.md 第三至八部分同步。

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

tests/test_build_ceus.py

@@ -277,3 +277,23 @@ def test_run_dir_without_snapshot_stops(tmp_path: Path) -> None:
     run = write_run(tmp_path / "runs" / RUN_ID, tmp_path / "delivery", {"U001": LOCATED}, [])
     (run / "snapshot" / "snapshot.json").unlink()
     _assert_stops(tmp_path, run, FileNotFoundError)
+
+
+@pytest.mark.parametrize(
+    ("extra", "remove"),
+    [
+        ("B0.tmp", None),  # B0.png 与同主干的 B0.tmp 并存：多一个文件
+        ("B0.jpg", "B0.png"),  # 只有 B0.jpg：扩展名不是 .png
+    ],
+)
+def test_keyframe_files_must_be_exactly_slot_pngs(
+    tmp_path: Path, extra: str, remove: str | None
+) -> None:
+    run = write_run(tmp_path / "runs" / RUN_ID, tmp_path / "delivery", {"U001": ("B0", "D1")}, [])
+    folder = run / "U001" / "keyframes"
+    (folder / extra).write_bytes((folder / "B0.png").read_bytes())
+    if remove is not None:
+        (folder / remove).unlink()
+    with pytest.raises(ValueError, match="定位到的槽位不一致"):
+        _build(tmp_path, 1, run)
+    assert not (tmp_path / "library").exists()