Look up complete documentation for a JoinQuant API function by exact name. 查询聚宽API函数的完整文档，包括参数列表、返回值和示例代码。

Args: function_name: Exact function name (e.g. 'get_price', 'get_fundamentals')

Search JoinQuant API docs by keyword (English or Chinese). 搜索API文档，支持英文和中文关键词搜索（函数名、中文名、描述、调用签名）。

Args: keyword: Search term in English or Chinese

List all API functions in a specific documentation section. 列出某个文档分类下的所有API函数。

Args: section: Section name (e.g. '获取股票数据', '获取融资融券标的列表')

Search API docs within a specific section only. 在指定文档分类中搜索API函数。

Args: keyword: Search term in English or Chinese section: Section name to search within (e.g. '获取股票数据')

List all available JoinQuant API function names, grouped by section. 列出所有可用的聚宽API函数名，按文档分类分组。

Use this to discover what functions are available before looking up specific ones.

Look up all column definitions for a JoinQuant data table. 查询聚宽数据表的所有字段定义（字段名、类型、含义）。

Critical for get_fundamentals queries where exact column names are needed.

Args: table_name: Table name (e.g. 'balance_sheet', 'income_statement')