fix(codex): drop transient rs_tmp reasoning replay state

tests/agent/test_codex_responses_adapter.py

@@ -0,0 +1,63 @@
+from types import SimpleNamespace
+
+from agent.codex_responses_adapter import _normalize_codex_response
+
+
+def test_normalize_codex_response_drops_transient_rs_tmp_reasoning_items():
+    response = SimpleNamespace(
+        status="completed",
+        output=[
+            SimpleNamespace(
+                type="reasoning",
+                id="rs_tmp_123",
+                encrypted_content="opaque-transient",
+                summary=[],
+            ),
+            SimpleNamespace(
+                type="reasoning",
+                id="rs_456",
+                encrypted_content="opaque-stable",
+                summary=[SimpleNamespace(text="stable summary")],
+            ),
+            SimpleNamespace(
+                type="message",
+                role="assistant",
+                status="completed",
+                content=[SimpleNamespace(type="output_text", text="done")],
+            ),
+        ],
+    )
+
+    assistant_message, finish_reason = _normalize_codex_response(response)
+
+    assert finish_reason == "stop"
+    assert assistant_message.content == "done"
+    assert assistant_message.codex_reasoning_items == [
+        {
+            "type": "reasoning",
+            "encrypted_content": "opaque-stable",
+            "id": "rs_456",
+            "summary": [{"type": "summary_text", "text": "stable summary"}],
+        }
+    ]
+
+
+def test_normalize_codex_response_treats_summary_only_reasoning_as_incomplete():
+    response = SimpleNamespace(
+        status="completed",
+        output=[
+            SimpleNamespace(
+                type="reasoning",
+                id="rs_tmp_789",
+                encrypted_content="opaque-transient",
+                summary=[SimpleNamespace(text="still thinking")],
+            )
+        ],
+    )
+
+    assistant_message, finish_reason = _normalize_codex_response(response)
+
+    assert finish_reason == "incomplete"
+    assert assistant_message.content == ""
+    assert assistant_message.reasoning == "still thinking"
+    assert assistant_message.codex_reasoning_items is None