Fix line ending inconsistencies in codecov integration

[Copilot]

The codecov integration PR had line ending conflicts preventing merge. README.md used CRLF line terminators while the repository standard is LF.

Changes:

• Normalized README.md to LF line endings (291 lines affected)
• Fixed missing newline terminator in .github/workflows/test.yml

The codecov integration remains intact:

• pytest coverage reporting with --cov-branch --cov-report=xml
• Codecov action upload with codecov/codecov-action@v5
• pytest-cov dependency in pyproject.toml
• Coverage badge in README

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