移除残留的KnowU系统，修复gemini请求的思考签名问题

pytests/test_gemini_thought_signatures.py

@@ -0,0 +1,72 @@
+import base64
+import sys
+from types import ModuleType, SimpleNamespace
+
+
+config_module = ModuleType("src.config.config")
+
+
+class _ConfigManagerStub:
+    def get_model_config(self) -> SimpleNamespace:
+        return SimpleNamespace(api_providers=[])
+
+    def register_reload_callback(self, _: object) -> None:
+        return None
+
+
+config_module.config_manager = _ConfigManagerStub()
+sys.modules.setdefault("src.config.config", config_module)
+
+from src.llm_models.model_client import gemini_client
+from src.llm_models.payload_content.message import MessageBuilder, RoleType
+from src.llm_models.payload_content.tool_option import ToolCall
+
+
+def _encode_signature(value: bytes) -> str:
+    return base64.b64encode(value).decode("ascii")
+
+
+def test_convert_messages_preserves_gemini_function_call_signature_and_tool_result_id() -> None:
+    thought_signature = b"gemini-signature"
+    tool_call = ToolCall(
+        call_id="call-1",
+        func_name="reply",
+        args={"msg_id": "42"},
+        extra_content={"google": {"thought_signature": _encode_signature(thought_signature)}},
+    )
+    assistant_message = MessageBuilder().set_role(RoleType.Assistant).set_tool_calls([tool_call]).build()
+    tool_message = (
+        MessageBuilder()
+        .set_role(RoleType.Tool)
+        .set_tool_call_id("call-1")
+        .set_tool_name("reply")
+        .add_text_content('{"ok": true}')
+        .build()
+    )
+
+    contents, _ = gemini_client._convert_messages([assistant_message, tool_message])
+
+    assistant_part = contents[0].parts[0]
+    assert assistant_part.function_call is not None
+    assert assistant_part.function_call.id == "call-1"
+    assert assistant_part.function_call.name == "reply"
+    assert assistant_part.thought_signature == thought_signature
+
+    tool_part = contents[1].parts[0]
+    assert tool_part.function_response is not None
+    assert tool_part.function_response.id == "call-1"
+    assert tool_part.function_response.name == "reply"
+    assert tool_part.function_response.response == {"ok": True}
+
+
+def test_convert_messages_injects_dummy_signature_for_first_historical_tool_call() -> None:
+    tool_calls = [
+        ToolCall(call_id="call-1", func_name="reply", args={"msg_id": "1"}),
+        ToolCall(call_id="call-2", func_name="reply", args={"msg_id": "2"}),
+    ]
+    assistant_message = MessageBuilder().set_role(RoleType.Assistant).set_tool_calls(tool_calls).build()
+
+    contents, _ = gemini_client._convert_messages([assistant_message])
+
+    assert contents[0].parts[0].thought_signature == gemini_client.GEMINI_FALLBACK_THOUGHT_SIGNATURE
+    assert contents[0].parts[1].thought_signature is None