Hash Map for Pair Sums and Duplicates

An Atos monitoring pipeline receives an unsorted array of integer event codes. Implement a function that identifies both distinct value pairs whose sum equals a target and values that occur at least twice, using hash-based lookups.

Return a dictionary with two keys: pairs, containing each distinct pair as a two-element list in the order it is first discovered, with the smaller value first; and duplicates, containing each duplicated value once in the order it reaches its second occurrence.

Formal Specification

• Input: nums, a list of integers, and target, an integer.
• Output: A dictionary of the form {"pairs": list[list[int]], "duplicates": list[int]}.
• A pair uses two different array positions, even when both values are equal.
• Each distinct value pair and duplicate value must appear only once.
• Return empty lists when no matching pair or duplicate exists.