兼容 OpenAI Chat Completions 协议，便于接入已有 Agent / SDK。地图相关结构化结果放在 choices[].metadata 中，字段含义与「流式对话」返回值一致。

请求示例：

{
    "messages": [
        {
            "role": "user",
            "content": "开车去故宫顺路去趟颐和园"
        }
    ],
    "stream": true,
    "metadata": {
        "id": "86abfeb7c72ee73d47d029a7d8ec985a",
        "loc_lng": 116.27988,
        "loc_lat": 40.050675,
        "coord_type": "bd09ll",
        "ret_coord_type": "bd09ll",
        "reset_context": "1"
    }
}

返回示例：

{
    "id": "1766129615915480383",
    "object": "chat.completion.chunk",
    "created": 1766129616,
    "model": "",
    "choices": [
        {
            "index": 0,
            "delta": {
                "role": "assistant",
                "content": "",
                "reasoning": "正在为你查找故宫,颐和园 "
            },
            "metadata": {
                "session_id": "789878107007000576",
                "query": "开车去故宫顺路去趟颐和园",
                "thought_data": {
                    "prefix": "正在为你查找",
                    "suffix": "",
                    "keywords": [
                        "故宫",
                        "颐和园"
                    ]
                },
                "answer_type": "gptmodel_thought"
            }
        }
    ]
}

与「同步对话」一致。