Deel may need to determine how many workers are simultaneously available during a scheduling period. Given availability windows, return the maximum number of workers whose windows overlap at any moment.
Treat every interval as half-open, [start, end): a worker is available at start but not at end. This means a window ending at time t does not overlap one starting at time t.
Implement max_concurrent_windows(intervals), where intervals is a non-empty list of [start, end] integer pairs. Return an integer representing the largest number of intervals active at the same time.
def max_concurrent_windows(intervals):