Add test cases and improve binary search correctness

[Shakir2005-s]

Description of Change

Fixed and improved binary search implementation in C++.

Changes:

• Fixed edge case handling for empty arrays
• Improved indexing safety using signed integers
• Added additional test cases for correctness verification
• Ensured proper binary search behavior on sorted arrays

This improves correctness, safety, and test coverage of the implementation.

Checklist

• Added description of change
• Added file name matches File name guidelines
• Added tests and example, test must pass
• Added documentation so that the program is self-explanatory and educational - Doxygen guidelines
• Relevant documentation/comments is changed or added
• PR title follows semantic commit guidelines
• Search previous suggestions before making a new one, as yours may be a duplicate.
• I acknowledge that all my contributions will be made under the project's license.

Notes:
Improved binary search implementation with safer indexing and added test coverage for edge cases including empty arrays and negative values.