Timsort optimization/conformity

The current Timsort implementation does sort the input list but doesn't perfectly conform to the Wikipedia description in that it doesn't employ insertion sort.

The given description isn't perfectly clear as to how the algorithm is meant to work and implementations found online vary in their approach.

The issue names no file, test, or entry point. Start by locating the Timsort implementation in this C library, compare it with the Wikipedia description and the project's sorting behavior, and use the visualizer where helpful. Done means the implementation includes the requested insertion-sort behavior while continuing to sort correctly.

Written by the indexing model from the issue text.