📋 JSON 字段说明
[
{
"subject": "数学",
"grade": "初三",
"term": "下学期",
"chapter": "第27章 相似",
"section": "27.2 相似三角形",
"type": "解答题",
"difficulty": "3（1=容易 2=基础 3=中档 4=较难 5=极难）",
"content": "题干，公式用 $...$ 包裹",
"options": ["A. 4","B. 6","C. 8","D. 10"],
"answer": "答案",
"analysis": "解析",
"image_url": "",
"knowledge_point": ["知识点"],
"good_tags": ["高频题","易错题"],
"good_reason": "好题理由",
"diagram_json": "",
"diagram_svg_url": ""
}
]
初中：grade=初一/初二/初三，term=上学期/下学期，chapter=第27章 相似，section=27.2 相似三角形
高中：grade=高一/高二/高三，term=必修一/必修二/选择性必修一，chapter=第6章 平面向量，section=6.1 平面向量的概念