feat: add cached prompt tokens and reported model to response types

tests/unit/test_types.py

@@ -49,6 +49,29 @@ class TestLLMResponse:
         assert resp.usage_source == "measured"
         assert resp.structured_data is None
 
+    def test_observability_fields_default_to_none(self):
+        """issue #3: None = 该源未上报,与"上报了但是 0"区分(0 是真实零命中)。"""
+        resp = LLMResponse("c", "t", "m", "p", 1, 2, 3, None, None, False, "cid")
+        assert resp.cached_prompt_tokens is None
+        assert resp.model_reported is None
+        filled = LLMResponse(
+            "c",
+            "t",
+            "m",
+            "p",
+            1,
+            2,
+            3,
+            None,
+            None,
+            False,
+            "cid",
+            cached_prompt_tokens=0,
+            model_reported="MiniMax-Text-01-250321",
+        )
+        assert filled.cached_prompt_tokens == 0  # 真实零命中,不得与 None 混同
+        assert filled.model_reported == "MiniMax-Text-01-250321"
+
     def test_frozen(self):
         resp = LLMResponse("c", "t", "m", "p", 1, 2, 3, None, None, False, "cid")
         with pytest.raises(dataclasses.FrozenInstanceError):
@@ -222,6 +245,8 @@ class TestAuxTypes:
             raw={"id": "x"},
         )
         assert s.raw["id"] == "x"
+        # issue #3: 新字段带默认值,不填也能构造(OCR 等其他 transport 零改动)
+        assert s.cached_prompt_tokens is None and s.model_reported is None
 
 
 class TestOcrTypes: