Publish to PyPI

[slusset]

Summary

Make the package installable via pip install ehr-writeback for anyone.

What to do

• Set up trusted publishing via GitHub Actions (OIDC, no API tokens)
• Add release workflow: tag → build → publish to PyPI
• Verify pip install ehr-writeback works in a clean environment
• Add PyPI badge to README

Acceptance criteria

• pip install ehr-writeback installs from PyPI
• GitHub release triggers automatic publish
• README has PyPI version badge

[IlyasFardaouix]

I think we're missing the OIDC setup for GitHub Actions, which is required for trusted publishing. Can you confirm that you've added the GITHUB_TOKEN and GITHUB_REPOSITORY secrets to your workflow file, and also configured OIDC in the GitHub Actions settings for your repository?

[slusset]

Completed in PRs #12 and #13. The release workflow is now in place, PyPI trusted publishing succeeded for version 0.1.0a1, and install verification passed ().