weekdayName static method
Returns the Chinese weekday name for weekday (1 = Monday, 7 = Sunday).
If short is true, returns a single character; otherwise a two-character label.
Implementation
static String weekdayName(int weekday, {bool short = true}) {
const shortNames = ['一', '二', '三', '四', '五', '六', '日'];
const longNames = ['周一', '周二', '周三', '周四', '周五', '周六', '周日'];
final index = (weekday - 1) % 7;
return short ? shortNames[index] : longNames[index];
}