feat(utils): add parse date range to extract start&end date

[magazian]

Involved Issue / 该 PR 相关 Issue

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Example for the Proposed Route(s) / 路由地址示例

NOROUTE

New RSS Route Checklist / 新 RSS 路由检查表

• New Route / 新的路由
  • Follows Script Standard / 跟随 路由规范
• Anti-bot or rate limit / 反爬/频率限制
  • If yes, do your code reflect this sign? / 如果有, 是否有对应的措施?
• Date and time / 日期和时间
  • Parsed / 可以解析
  • Correct time zone / 时区正确
• New package added / 添加了新的包
• Puppeteer

Note / 说明

Adds a new utility lib/utils/parse-date-range.ts that extracts a start date and end date from free-form date range strings, returning both in YYYY-MM-DD format, can support both CN&EN date range format.
This utility was originally written in the chnmuseum route. It is now promoted to a standalone, well-tested helper so that other routes (e.g. museum, gallery, and exhibition feeds) can reuse it directly instead of reimplementing the same logic.