Closes #88
This pull request updates and improves the CI workflow configuration by renaming the workflow file, upgrading GitHub Actions versions, expanding test coverage to Windows, and refining test and dependency installation steps. These changes enhance compatibility, reliability, and future-proof the CI pipeline.

CI workflow upgrades:

• Renamed .github/workflows/simple-ci.yml to .github/workflows/ci.yml for clarity and standardization.
• Updated key GitHub Actions to their latest major versions (actions/cache to v4, actions/checkout to v5, and actions/setup-python to v6), improving security and performance. [1] [2] [3]

Test matrix and execution improvements:

• Expanded the test matrix to include windows-latest alongside ubuntu-latest and macos-latest, with a new shell default configuration to ensure cross-platform compatibility.
• Split test execution steps by OS and adjusted activation commands for each platform, ensuring correct environment setup for Linux, macOS, and Windows runners.

Dependency installation refinements:

• Removed the --no-root flag from poetry install commands to ensure the root project is installed during CI, which is necessary for proper testing.