checklist.md

1. Implement only Array.prototype.sort2. Do NOT override Array.prototype.sort.
2. Keep the given scaffold: define sort2 via [].__proto__.sort2 = function(compareFunction) { ... } inside applyCustomSort in src/arrayMethodSort.js.
3. sort2 must sort the array in place and return the original array (same reference, not a copy).
4. When compareFunction is not provided, compare elements as strings (their default string representation, by character codes). Example: [3, 12, 2, 11].sort2() must return [11, 12, 2, 3].
5. When compareFunction is provided, use its return value to order elements: negative → first before second, positive → first after second.
6. Do NOT call the built-in Array.prototype.sort in your implementation. Write your own sorting algorithm (bubble sort, insertion sort, etc.).