Remove code duplication between EvalOperator and handleOperator in rpn package

- Added executeOperator helper method to handle both standard and hyper operators
- Updated handleOperator, EvalOperator, and ResultStack to use executeOperator
- Removed handleHyperOperatorWithRegistry method (no longer needed)
- Consolidated duplicate operator handling logic into single helper

This improves code maintainability by following DRY principle - operator
handling logic is now in one place (executeOperator).

All tests pass including hyper operator tests. 1 file changed, 23 insertions(+),
28 deletions(-).

0 files changed, 0 insertions, 0 deletions