Description of Change

Added an implementation of IntroSort (Introspective Sort) in C.
IntroSort is a hybrid sorting algorithm that begins with QuickSort, switches to HeapSort when the recursion depth exceeds a limit, and uses InsertionSort for small subarrays.
This approach achieves both fast average performance and optimal worst-case behavior — the same principle used by std::sort in C++.

References

Implements #1488

Checklist

• Added description of change
• Added file name matches File name guidelines
• Added tests and example, test must pass
• Relevant documentation/comments is changed or added
• PR title follows semantic commit guidelines
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Notes: Added a practical, high-performance hybrid sorting algorithm combining QuickSort, HeapSort, and InsertionSort for balanced performance and guaranteed O(n log n) complexity in the worst case.