implementing converse benchmark

[agoel00]

Description

This PR adds a new benchmark implementation in the MASEval framework based on https://arxiv.org/abs/2511.05359.

Type of Change

• Bug fix (non-breaking change that fixes an issue)
• New feature (non-breaking change that adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation update
• Code quality improvement (refactoring, formatting, etc.)

Checklist

Contribution

• I have read the CONTRIBUTING.md guide.
• Commits follow "How to write a good git commit message"

Documentation

• Added/updated docstrings for new/modified functions as instructed CONTRIBUTING.md
• Updated relevant documentation in docs/ (if applicable)
• Tag github issue with this PR (if applicable)

Changelog

• Added entry to CHANGELOG.md under [Unreleased] section
  • Use Added section for new features
  • Use Changed section for modifications to existing functionality
  • Use Fixed section for bug fixes
  • Use Removed section for deprecated/removed features
• OR this is a documentation-only change (no changelog needed)

Example:
- Support for multi-agent tracing (PR:#123)

Architecture (if applicable)

• Core/Interface separation: Changes in maseval/core/ do NOT import from maseval/interface/
• Dependencies: New core dependencies added sparingly; framework integrations go to optional dependencies

Additional Notes