fix(soak): 合成观察那两档不该逐字比对，判据写错了

193 次真实运行报了 9 处击穿，核下来是判据的错不是库的错：动作被拒绝或环境故障时，库
刻意不把执行器给的观察回填进历史，而是换成合成观察那一段。两个字段承载的本来就不是同
一件事——一个是执行器原文的留痕，一个是真正喂给模型的文本。

改判据时顺着源码发现被替换的是三列不是一列：观察文本、是否合成、截断字符数在那两档下
全部由库填。所以旧判据在环境故障那一档上必然也会误报，只是这 193 次里没撞上真的环境
故障；截断数那一列则是恰好两边都是 0，潜伏着没炸。

现在 executed 档三列仍然逐字比对，另两档改成断言步记录的「是否合成」标记确实立起来了——
库既然替换了观察，不立这个标记才是真出了问题。

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

tools/soak/tests/test_scoreboard.py

@@ -221,6 +221,41 @@ def edit_log(path: Path, edit: Callable[[list[dict]], list[dict]]) -> None:
     )
 
 
+def reshape_step(
+    path: Path,
+    *,
+    step_idx: int,
+    status: str,
+    outcome_observation: str,
+    step_observation: str,
+    outcome_is_synthetic: bool = False,
+    step_is_synthetic: bool = False,
+    outcome_truncated: int = 0,
+    step_truncated: int = 0,
+) -> None:
+    """把某一步改写成「执行器那侧与步记录那侧的观察不是同一段」的样子。
+
+    `build_records` 造出来的每一步都是 executed 且两侧逐字相同，而真实产物里被拒绝的动作
+    与环境故障那两档不长这样——库会替换回填进历史的观察。反例都从这里造。
+    """
+
+    def edit(items: list[dict]) -> list[dict]:
+        for item in items:
+            if item["record"] != "step_completed" or item["step"]["step_idx"] != step_idx:
+                continue
+            item["action_outcome"]["status"] = status
+            item["action_outcome"]["observation"] = outcome_observation
+            item["action_outcome"]["observation_is_synthetic"] = outcome_is_synthetic
+            item["action_outcome"]["observation_truncated_chars"] = outcome_truncated
+            item["step"]["action_status"] = status
+            item["step"]["observation"] = step_observation
+            item["step"]["observation_is_synthetic"] = step_is_synthetic
+            item["step"]["observation_truncated_chars"] = step_truncated
+        return items
+
+    edit_log(path, edit)
+
+
 def verdict_of(scoreboard, name: str) -> Verdict:
     for item in scoreboard.invariants:
         if item.name == name:
@@ -464,6 +499,101 @@ def test_outcome_disagreeing_with_step_record_is_a_breach(tmp_path: Path) -> Non
     assert_breached(evaluate(tmp_path), "动作结果与步记录一致")
 
 
+def test_executed_step_with_a_different_observation_is_a_breach(tmp_path: Path) -> None:
+    """executed 档是原样透传，两侧观察必须逐字相同。"""
+    materialize(tmp_path)
+    reshape_step(
+        tmp_path / "soak-0001.jsonl",
+        step_idx=0,
+        status="executed",
+        outcome_observation="环境返回的原文",
+        step_observation="换了一段别的",
+    )
+    assert_breached(evaluate(tmp_path), "动作结果与步记录一致")
+
+
+@pytest.mark.parametrize(
+    ("status", "executor_text", "executor_is_synthetic"),
+    [
+        (
+            "not_executed",
+            "工具不存在：'final_answer'，本次可见的是 "
+            "['read_document', 'grep_document', 'write_note']",
+            True,
+        ),
+        ("env_error", "容器没了：connection refused", False),
+    ],
+)
+def test_replaced_observation_is_not_a_breach(
+    tmp_path: Path, status: str, executor_text: str, executor_is_synthetic: bool
+) -> None:
+    """未执行与环境故障两档，库刻意换掉回填进历史的观察，两侧文本不同是正常的。
+
+    数据形状照 `tools/soak/runs/full/govdoc-15-execute.jsonl` 第 36 行那条真实记录造：
+    执行器那侧留的是「工具不存在」的原文，步记录那侧是合成的那段提示。截断数也一起换掉
+    （库在这两档下一律填 0），所以它同样不该被比对。
+    """
+    materialize(tmp_path)
+    reshape_step(
+        tmp_path / "soak-0001.jsonl",
+        step_idx=0,
+        status=status,
+        outcome_observation=executor_text,
+        step_observation=(
+            "[动作被拒绝，这一步没有执行任何工具]\n"
+            "请对照工具清单检查工具名与参数，然后重新输出一个 JSON 对象。"
+        ),
+        outcome_is_synthetic=executor_is_synthetic,
+        step_is_synthetic=True,
+        outcome_truncated=40,
+        step_truncated=0,
+    )
+    assert verdict_of(evaluate(tmp_path), "动作结果与步记录一致") is Verdict.PASSED
+
+
+@pytest.mark.parametrize("status", ["not_executed", "env_error"])
+def test_replaced_observation_without_the_synthetic_flag_is_a_breach(
+    tmp_path: Path, status: str
+) -> None:
+    """库既然替换了观察，就必须把 observation_is_synthetic 立起来，不立才是真出了问题。"""
+    materialize(tmp_path)
+    reshape_step(
+        tmp_path / "soak-0001.jsonl",
+        step_idx=0,
+        status=status,
+        outcome_observation="执行器给的原文",
+        step_observation="库换上去的那一段",
+        outcome_is_synthetic=False,
+        step_is_synthetic=False,
+    )
+    assert_breached(evaluate(tmp_path), "动作结果与步记录一致")
+
+
+@pytest.mark.parametrize("status", ["not_executed", "env_error"])
+def test_status_still_has_to_agree_in_every_branch(tmp_path: Path, status: str) -> None:
+    """状态与完成标记这两项三档下都比：观察分档，它们不分。"""
+    materialize(tmp_path)
+    reshape_step(
+        tmp_path / "soak-0001.jsonl",
+        step_idx=0,
+        status=status,
+        outcome_observation="执行器给的原文",
+        step_observation="库换上去的那一段",
+        outcome_is_synthetic=True,
+        step_is_synthetic=True,
+    )
+    edit_log(
+        tmp_path / "soak-0001.jsonl",
+        lambda items: [
+            {**item, "step": {**item["step"], "action_status": "executed"}}
+            if item["record"] == "step_completed" and item["step"]["step_idx"] == 0
+            else item
+            for item in items
+        ],
+    )
+    assert_breached(evaluate(tmp_path), "动作结果与步记录一致")
+
+
 def test_prompt_chars_going_backwards_is_a_breach(tmp_path: Path) -> None:
     materialize(tmp_path, steps=3)