feat: add tribonacci using matrix exponentiation

[Hxrshthetic]

Description of Change

This PR adds an implementation of the Tribonacci sequence using matrix exponentiation.

The implementation computes the nth Tribonacci number efficiently in O(log n) time using a 3x3 transformation matrix and binary exponentiation.

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
• 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 tribonacci implementation using matrix exponentiation with O(log n) complexity.

[Hxrshthetic]

@Panquesito7 and @realstealthninja
Please review this.