Add wake factor computation (loss and kick factors) with postprocessing function and test in my_test folder

[saraadastan]

📝 Pull Request Summary

This PR adds a new postprocessing feature to compute wake factors from simulation results.

Specifically, it introduces the computation of:

• Longitudinal loss factor
• Transverse kick factors (kx, ky)

The implementation is consistent with the Wakis workflow by using WakeSolver.load_results() for reading data, ensuring compatibility with MPI runs.

🔧 Changes Made

• Added compute_wake_factors function in postprocessing module
• Implemented time-domain computation of loss and kick factors
• Integrated reading of results using WakeSolver.load_results()
• Added test script/example to validate the functionality

✅ Checklist

• Code follows the project's style and guidelines
• Added tests for new functionality
• Updated documentation (optional for now unless you added docs)
• Verified that changes do not break existing functionality

📌 Related Issues / PRs

N/A