Upload pytest coverage to GitHub from the latest Python CI job

[Copilot]

This PR adds code coverage upload to the CI workflow by publishing the pytest-generated Cobertura report to GitHub, scoped to the latest Python version in the test matrix.

• CI workflow updates

  • Added code-quality: write permission to the tox job so coverage upload is authorized.
  • Kept the existing Python matrix intact and limited coverage upload behavior to 3.14 (latest configured version).

• Coverage artifact generation

  • Extended test invocation options for the 3.14 matrix run to emit coverage.xml:
    • --cov-report=xml:coverage.xml
  • Left non-latest matrix runs unchanged to avoid redundant uploads.

• Coverage upload step

  • Added actions/upload-code-coverage@v1 gated by if: matrix.py == '3.14'.
  • Configured required inputs:
    • file: coverage.xml
    • language: Python
    • label: code-coverage/pytest

- name: Upload code coverage report
  if: matrix.py == '3.14'
  uses: actions/upload-code-coverage@v1
  with:
    file: coverage.xml
    language: Python
    label: code-coverage/pytest

• Fixes Add code coverage to the workflow #67

[Copilot]

Pull request overview

Adds GitHub-native code coverage reporting to the CI workflow by generating a Cobertura (coverage.xml) report from the pytest run on the latest Python version in the matrix and uploading it to GitHub.

Changes:

• Grants the tox job code-quality: write permission to authorize coverage uploads.
• Extends pytest options for the 3.14 matrix run to emit coverage.xml.
• Uploads coverage.xml via actions/upload-code-coverage@v1, gated to Python 3.14.

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[hspaans]

Code Quality uploads aren't currently supported for personal repositories. Closing issue until support is available.