Improve test configuration and CI setup

[subchat]

Updates test configuration for better CI compatibility.

[github-actions]

No linked issues found. Please link an issue in your pull request description or title.

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[github-actions]

❌ Infrastructure File Protection

This PR modifies protected infrastructure files:

• tox.ini (1 changes)

Only repository maintainers are allowed to modify infrastructure files (including .github/, build configuration, and repository documentation).

Note: If these are only formatting changes, please:

1. Revert changes to .github/ files
2. Use ./autoformat.sh to format only source code directories
3. Avoid running formatters on infrastructure files

If structural changes are necessary:

1. Open an issue describing the needed infrastructure changes
2. A maintainer will review and implement the changes if approved

For more information, see our Contributing Guidelines.