Add comprehensive visualization tools for data science workflows

[dgenio]

• Add plot_propensity_distribution for propensity score analysis
• Add plot_dr_results for DR/SNDR evaluation visualization
• Add plot_calibration_curve and plot_roc_curve for model assessment
• Add plot_diagnostics_summary for comprehensive diagnostics
• Add create_dashboard for all-in-one visualization
• Include matplotlib and seaborn integration
• Add comprehensive test suite for visualization functions
• Update init.py to export visualization functions

Pull Request

📋 Description

Type of Change

• 🐛 Bug fix (non-breaking change which fixes an issue)
• ✨ New feature (non-breaking change which adds functionality)
• 💥 Breaking change (fix or feature that would cause existing functionality to not work as expected)
• 📚 Documentation update
• 🧹 Code refactoring (no functional changes)
• ⚡ Performance improvement
• 🧪 Test improvements
• 🔧 Build/CI improvements

🔗 Related Issues

• Fixes #
• Related to #

🧪 Testing

Test Coverage

• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• I have added integration tests if applicable

Manual Testing

• Tested locally with make check
• Tested with example scripts
• Tested edge cases

Test commands run:

# List the commands you used to test
make check
python examples/quickstart.py

📝 Changes Made

Code Changes

API Changes

• No API changes
• Backward compatible API additions
• Breaking API changes (requires major version bump)

API changes:

📚 Documentation

• I have updated the documentation accordingly
• I have updated docstrings for new/modified functions
• I have added examples if applicable
• I have updated the CHANGELOG.md

✅ Checklist

Code Quality

• My code follows the project's style guidelines
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• My changes generate no new warnings
• I have run ruff check and ruff format
• I have run mypy type checking

Testing & CI

• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• All CI checks pass
• Code coverage is maintained or improved

Documentation & Communication

• I have made corresponding changes to the documentation
• My commit messages follow the conventional commit format
• I have updated the CHANGELOG.md if applicable

🔍 Review Notes

Focus Areas

Questions for Reviewers

📸 Screenshots/Examples

# Example usage of new feature
import skdr_eval

# Your example here

🚀 Deployment Notes

• No special deployment considerations
• Requires database migrations
• Requires environment variable changes
• Requires dependency updates

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Additional Context: