feat: add Round Robin CPU scheduling algorithm

[Shubhangam-Singh]

Implements preemptive Round Robin (RR) scheduling in C++17 following the TheAlgorithms/C-Plus-Plus code style.

Key features:

• Supports processes with different arrival times
• Uses std::queue<uint32_t> for the circular ready queue
• Class template RoundRobin<S,T,E> with addProcess() / scheduleForRR() / printResult() methods, wrapped in namespace cpu_scheduling_algorithms::round_robin
• Doxygen comments on all types, functions, and parameters
• 5 self-test cases validated with assert(), including:
  • Same-arrival-time scenario (quantum=2, three processes)
  • Single-process trivial case (no waiting, no preemption)
  • Burst == quantum case (no preemption, sequential completion)
  • Duplicate process ID guard
  • Different arrival times cross-validated against a reference impl

Description of Change

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: