Find Pairs With Minimum Difference

How would you find all pairs of numbers with the minimum difference in an array?

Implement the function below. Return every distinct pair of values whose absolute difference is minimum. Each pair must be written as [smaller, larger], and the result must be sorted lexicographically. If fewer than two numbers are provided, return an empty list.

Function Contract

minimum_difference_pairs(nums) accepts a list of integers and returns a list of two-element lists. Duplicate value pairs should appear only once, even when multiple occurrences create the same pair.