60s CNB知识库

交互模式：
  python 60s.py                    # 进入交互菜单

快捷指令模式：
  python 60s.py latest             # 下载最新内容
  python 60s.py date 2025-10-01    # 下载指定日期
  python 60s.py month 10           # 下载当前年份的指定月份
  python 60s.py month 10 2025      # 下载指定年份和月份
  python 60s.py range 2025-10-01 2025-10-07  # 下载日期范围
  python 60s.py help               # 显示此帮助信息

示例：
  python 60s.py latest
  python 60s.py date 2025-09-15
  python 60s.py month 9
  python 60s.py month 9 2025
  python 60s.py range 2025-09-01 2025-09-30