test(review): 新增 pytest 离线回归网，锁定 dwg_review 既有行为

在改动审查流水线（确定性检查前置 / 结论结构化 / 证据交叉校验）之前，
先立一张离线、确定性、秒级的回归网。

- tests/fakes.py：假 LLM + 假 MCP 基座 + 响应构造器（ok_text/ok_image/err）
  + make_ctx/make_evidence，绝不触网、不读密钥
- 10 个模块共 134 用例：
  mcp_client / llm_client / cad_tools / checklist / config /
  planning / evidence / review / report / annotator
- pytest.ini（testpaths=tests）+ requirements-dev.txt + 根 conftest.py
  （sys.path + RENDER_WAIT=0 / REPORT_DIR=tmp fixture）

tests/test_checklist.py

@@ -0,0 +1,72 @@
+"""`dwg_review.checklist` 单元测试。"""
+
+import json
+
+from dwg_review.checklist import (
+    DEFAULT_CHECKLIST,
+    build_system_prompt,
+    checklist_summary,
+    load_checklist,
+)
+
+
+def test_load_valid_checklist(tmp_path):
+    data = {
+        "name": "自定义清单",
+        "categories": [{"title": "类别A", "severity": "high", "checks": ["检查1"]}],
+    }
+    path = tmp_path / "cl.json"
+    path.write_text(json.dumps(data, ensure_ascii=False), encoding="utf-8")
+    loaded = load_checklist(path)
+    assert loaded["name"] == "自定义清单"
+    assert loaded["categories"][0]["title"] == "类别A"
+
+
+def test_load_missing_file_falls_back(tmp_path, capsys):
+    loaded = load_checklist(tmp_path / "nope.json")
+    assert loaded is DEFAULT_CHECKLIST
+    assert "无法加载审查清单" in capsys.readouterr().out
+
+
+def test_load_malformed_structure_falls_back(tmp_path, capsys):
+    path = tmp_path / "cl.json"
+    path.write_text(json.dumps({"name": "缺 categories"}), encoding="utf-8")
+    assert load_checklist(path) is DEFAULT_CHECKLIST
+    assert "结构异常" in capsys.readouterr().out
+
+
+def test_load_invalid_json_falls_back(tmp_path, capsys):
+    path = tmp_path / "cl.json"
+    path.write_text("{ not json", encoding="utf-8")
+    assert load_checklist(path) is DEFAULT_CHECKLIST
+    assert "无法加载审查清单" in capsys.readouterr().out
+
+
+def test_load_empty_categories_falls_back(tmp_path):
+    path = tmp_path / "cl.json"
+    path.write_text(json.dumps({"categories": []}), encoding="utf-8")
+    assert load_checklist(path) is DEFAULT_CHECKLIST
+
+
+def test_build_system_prompt_includes_categories_and_checks():
+    prompt = build_system_prompt(DEFAULT_CHECKLIST)
+    assert DEFAULT_CHECKLIST["name"] in prompt
+    for cat in DEFAULT_CHECKLIST["categories"]:
+        assert cat["title"] in prompt
+        assert f"严重度：{cat['severity']}" in prompt
+        for chk in cat["checks"]:
+            assert chk in prompt
+
+
+def test_build_system_prompt_tool_hint_toggle():
+    with_tools = build_system_prompt(DEFAULT_CHECKLIST, allow_tools=True)
+    without = build_system_prompt(DEFAULT_CHECKLIST, allow_tools=False)
+    assert "只读" in with_tools and "取证工具" in with_tools
+    assert "只读" not in without
+
+
+def test_checklist_summary_mentions_name_and_count():
+    summary = checklist_summary(DEFAULT_CHECKLIST)
+    assert DEFAULT_CHECKLIST["name"] in summary
+    assert str(len(DEFAULT_CHECKLIST["categories"])) in summary
+    assert DEFAULT_CHECKLIST["categories"][0]["title"] in summary