feat[probability]: add conditional probability algorithm

[SomrajBanik]

Description of Change

This PR adds an implementation of Conditional Probability to the probability section. It introduces a new file probability/conditional_probability.cpp that implements the mathematical formula for computing conditional probability P(A|B) = P(A ∩ B) / P(B).

It includes:

• 7 tests covering normal, edge case as well as error conditions
• All tests cases pass
• Function conditional_compute() takes two arguments and returns the required probability

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:
add new file at probability/conditional_probability.cpp containing conditional probability implementation.

[realstealthninja]

Thank you for your contribution!

[SomrajBanik]

Done.
Added e.what() asserts to tests 5, 6 and 7 so each one now checks the exact error message.
Added newline at EOF
Minor changes: Added relevant mathematical terms to Tests 2 & 3
Thanks for the review!

[realstealthninja]

Thanks for the contribution, could you disclose whether any LLM assistance was taken in the process of writing this pr?

[SomrajBanik]

Thanks for asking. I did not use LLM assistance for the core logic or structure, I studied how the other probability algorithms were written like geometric_dist.cpp and structured like them. I did use an LLM briefly to review the Doxygen documentation formatting before submitting to make sure the comments matched the project's documentation style, but the implementation itself was my own work.

[realstealthninja]

use mid when denoting bars in latex

[realstealthninja]

Thanks will be merged soon.

[SomrajBanik]

Thank You!!