Add comprehensive GitHub Actions automation and prepare v0.1.3 release

- Add CI workflow with multi-platform testing (Ubuntu, macOS, Windows)
- Add automatic PyPI publishing on GitHub releases
- Add release automation workflow for version tags
- Add post-publish validation workflow
- Bump version to 0.1.3 with comprehensive feature additions
- Update CHANGELOG.md with complete release notes
- Include setup guides for manual workflow deployment

Complete automation pipeline:
✅ CI testing on all platforms
✅ Automatic PyPI publishing
✅ Release creation from tags
✅ Package validation after publishing

Ready for production automation workflow\!