Linked-List Queue with Delete and Deduplication

Implement a queue whose state is stored in a hand-built singly linked list. The queue starts empty. Process operations from left to right, using the integer at the same index in values when an operation needs an argument.

The supported operations are:

• enqueue: append a new node containing values[i] at the tail in O(1) time.
• dequeue: remove the head in O(1) time and append its value to the result.
• delete: remove the first node, from the head, whose value equals values[i]. If no node matches, leave the queue unchanged.
• removeAllDuplicates: retain the first occurrence of every value and remove all later occurrences, preserving the relative order of the retained nodes.

Return the values produced by dequeue operations in encounter order. The value paired with dequeue or removeAllDuplicates is ignored.