Test code workflow 추가

[seohyunjun]

This pull request introduces a new CI workflow using GitHub Actions to automate linting and testing for the project. The workflow ensures code quality and compatibility across multiple Python versions.

Continuous Integration setup:

• Added .github/workflows/ci.yml to define a CI workflow that runs on pushes and pull requests targeting master and main branches.

Linting improvements:

• Configured a job to lint the codebase using Ruff, including both style checks and format checks.

Testing enhancements:

• Set up a test job to run the test suite using pytest and pytest-cov across Python versions 3.9, 3.10, 3.11, and 3.12, ensuring broad compatibility.