test(review): 把 5 处既有瑕疵锁成 *_known_gap 用例

让既有瑕疵可见，而不是被当成正确行为；改 1~3（确定性检查前置/结论结构化/
证据交叉校验）时可据此判断行为是否被改变。

- bbox_to_window 含非数值 → ValueError（上游只判长度）
- summarize / extract_issues 硬下标 f['frame'] → KeyError
- annotate 的 created 无去重（同 handle 产生重复批注）
- extract_issues 单行 ```json[...]``` 围栏剥离失败 → []
- result_json 文本 'null' → None（与「无 text 返回 default」语义易混）

tests/test_report.py

@@ -2,6 +2,8 @@
 
 import json
 
+import pytest
+
 from dwg_review.phases.report import extract_issues, save_report, summarize
 from tests.fakes import FakeLlmClient, make_ctx
 
@@ -44,6 +46,13 @@ def test_summarize_falls_back_to_raw_input_on_error():
     assert any("汇总失败" in line for line in logs)
 
 
+def test_summarize_missing_frame_key_known_gap():
+    """已知瑕疵：summarize 用硬下标 f['frame']，findings 缺该键直接 KeyError。"""
+    ctx = make_ctx(llm=FakeLlmClient(text="x"))
+    with pytest.raises(KeyError):
+        summarize(ctx, [{"finding": "缺 frame 键"}], log=lambda *a: None)
+
+
 # ---------------------------------------------------------------------------
 #  extract_issues
 # ---------------------------------------------------------------------------
@@ -85,6 +94,20 @@ def test_extract_issues_returns_empty_when_not_a_list():
     assert extract_issues(ctx, findings_fixture(), log=lambda *a: None) == []
 
 
+def test_extract_issues_single_line_fence_known_gap():
+    """已知瑕疵：围栏剥离依赖换行，单行 ```json[...]``` 会残留 json 前缀 → 解析失败。"""
+    llm = FakeLlmClient(text_script=['```json[{"frame": 1, "message": "z"}]```'])
+    ctx = make_ctx(llm=llm)
+    assert extract_issues(ctx, findings_fixture(), log=lambda *a: None) == []
+
+
+def test_extract_issues_missing_frame_key_known_gap():
+    """已知瑕疵：extract_issues 同样用硬下标 f['frame']，findings 缺该键直接 KeyError。"""
+    ctx = make_ctx(llm=FakeLlmClient(text="[]"))
+    with pytest.raises(KeyError):
+        extract_issues(ctx, [{"finding": "缺 frame 键"}], log=lambda *a: None)
+
+
 # ---------------------------------------------------------------------------
 #  save_report
 # ---------------------------------------------------------------------------