Two axis-aligned rectangles overlap when their projections on both the x-axis and y-axis intersect. If either axis has no overlap, the rectangles cannot overlap.

For axis ranges [ax1, ax2] and [bx1, bx2], they overlap when max(ax1, bx1) < min(ax2, bx2). Apply the same formula to the y-axis.

Check the negation first — rectangles do NOT overlap when one is entirely left, right, above, or below the other (four simple comparisons). Return early for non-overlap.