feat: add DeepSeek extreme reasoning tier

tests/test_agent_loop.py

@@ -962,3 +962,59 @@ def test_tool_events_render_one_friendly_completed_card() -> None:
     assert 'name="执行命令"' in rendered
     assert "2 passed" in rendered
     assert 'done="false"' not in rendered
+
+
+async def test_extreme_tier_preserves_reasoning_state_across_tool_turns(settings) -> None:
+    provider = ScriptedProvider(
+        [
+            {
+                "choices": [
+                    {
+                        "message": {
+                            "role": "assistant",
+                            "content": None,
+                            "reasoning_content": "provider-private-state",
+                            "tool_calls": [tool_call("1", "read_file", {"path": "notes.txt"})],
+                        },
+                        "finish_reason": "tool_calls",
+                    }
+                ]
+            },
+            {
+                "choices": [
+                    {
+                        "message": {"role": "assistant", "content": "检查完成"},
+                        "finish_reason": "stop",
+                    }
+                ]
+            },
+        ]
+    )
+    registry = RecordingRegistry()
+    store = RuntimeStore(settings.database_url)
+    await store.initialize()
+
+    async def callback(event_type, payload):
+        return None
+
+    try:
+        answer = await AgentLoop(provider, registry, store, max_tool_output_chars=10_000).run(
+            spec=get_model_spec("work-extreme"),
+            messages=[{"role": "user", "content": "读取 notes.txt 并检查内容"}],
+            identity=UserIdentity("u1", "", "", "user"),
+            raw_user_jwt="jwt",
+            chat_id="deepseek-reasoning",
+            callback=callback,
+        )
+    finally:
+        await store.close()
+
+    assert answer == "检查完成"
+    assert provider.requests[0]["provider"] == "deepseek"
+    assert provider.requests[0]["reasoning_effort"] == "max"
+    assistant_turn = next(
+        message
+        for message in provider.requests[1]["messages"]
+        if message.get("role") == "assistant" and message.get("tool_calls")
+    )
+    assert assistant_turn["reasoning_content"] == "provider-private-state"