feat(graph): Implement D'Esopo–Pape algorithm for shortest paths

[shimmer12]

This implementation adds the D’Esopo–Pape (Pape) algorithm for single-source shortest paths on graphs with non-negative edge weights, using a deque to prioritize vertex processing. It also includes unit tests that validate correctness on example graphs.

Description of Change

• Implemented D’Esopo–Pape SSSP using a deque-based relaxation order.
• Added adjacency construction helper and example driver.
• Provided assert-based unit tests for sample cases.
• Documented approach, complexity, and assumptions (non-negative weights) with Doxygen comments.

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: Adds deque-based Pape SSSP with tests and Doxygen; assumes non-negative weights and supports directed/undirected via adjacency setup.