按课表排每周专注时间和倒计时

只是写法示意，不是完整程序。

// ANS 课表单双周与周次区间匹配判定器 (ans-schedule-ics.ts)
export function isAnsCourseActiveInWeek(week: number, startW: number, endW: number, mode: "ALL" | "ODD" | "EVEN" = "ALL") {
  if (week < startW || week > endW) return false;
  return mode === "ALL" ? true : mode === "ODD" ? week % 2 === 1 : week % 2 === 0;
}