pub fn detect_date_format(labels: &[String]) -> Option<String>Expand description
Detect if labels look like dates and return a compact display format.
Checks a sample of labels for ISO date patterns (YYYY-MM-DD or YYYY-MM-DDTHH:MM:SS).
Returns a chrono strftime format string for compact display, or the special
QUARTER_FORMAT marker when all dates are quarter boundaries.