ConvexHull fix

[yadhu-vipin]

This PR fixes an issue in the ConvexHull class where the recursive method returned hull points in an unordered fashion due to the use of a HashSet. This caused algorithms that rely on vertex order, such as Rotating Calipers, to produce incorrect results (e.g., incorrect minimum bounding rectangle areas).

The fix preserves the counter-clockwise (CCW) order of the hull points while maintaining all points that lie on the convex polygon. This ensures compatibility with downstream geometric algorithms.

Changes:

• Replaced HashSet with LinkedHashSet or List + sorting to preserve order.
• Ensured deterministic CCW ordering starting from the bottom-most, left-most point.
• Updated test expectations to match the ordered output.

Impact:

• Algorithms like Rotating Calipers now compute correct values.
• Maintains correctness for all convex hull computations.