feat: implemented page replacement algorithms

[Satvik-Singh192]

Description

Added a complete Page Replacement Algorithm Simulator in C++.
This feature allows users to input the number of frames, page reference string, and choose among FIFO, LRU, and Optimal page replacement algorithms.
The simulator displays the frame table after each page request along with hit/miss status and final statistics (total hits, total misses, hit ratio).
Implemented in a single beginner-friendly C++ file with no external libraries, as required.

Semver Changes

• Patch (bug fix, no new features)
• Minor (new features, no breaking changes)
• Major (breaking changes)

Issues

Closes #65 — [Feature]: Page Replacement Algorithm Simulator

Checklist

• I have read the Contributing Guidelines.

[Satvik-Singh192]

@prajwal3114 please review my pull request sir