[akhila-pynam]

Description of Change

Converts Javadoc-style banner comments (/****************) to standard Doxygen comments (/** ... */) across the following files:

• sorting/selection_sort_iterative.cpp
• dynamic_programming/partition_problem.cpp
• geometry/graham_scan_algorithm.cpp
• geometry/graham_scan_functions.hpp

In doc/Doxyfile, JAVADOC_BANNER = NO is configured, which causes Doxygen to treat banner-style comments as regular C comments and ignore them. Because of this, the @file blocks are ignored and the files appear bold and unclickable on the documentation website. Converting them to standard Doxygen style resolves this issue.

Related to #3234

Checklist

• Added description of change
• 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: Fixes Doxygen rendering for sorting/selection_sort_iterative.cpp, dynamic_programming/partition_problem.cpp, geometry/graham_scan_algorithm.cpp, and geometry/graham_scan_functions.hpp.