Add Pong Game in C to /games

[tadeyemo32]

Description of Change

Added a simple Pong game implemented in C using the Raylib graphics library.
The game is placed in the /games/pong/ directory and includes:

• Cross-platform Makefile (macOS, Linux, Windows)
• A comprehensive README.md with build steps
• Full game source code (main.c)

References

N/A

Checklist

• Added description of change
• Added file name matches File name guidelines
• Added tests and example, test must pass (Game-based projects don’t use unit tests, so this may not apply)
• 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

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Notes:
This game demonstrates practical use of C in graphics, event handling, and game loop logic.
Although not a traditional algorithm, it can serve as an educational example under the /games directory.