Refactors .github/workflows/tests.yaml so that flake8, black, mypy,
pylint, and bandit each run as their own job in parallel with the test
job. This ensures a failure in one tool never blocks the others, and
contributors see full feedback from every tool on every CI run.
- Upgrades actions/checkout to v4 and actions/setup-python to v5
- All linter jobs are enforced (no continue-on-error)
- Test artifacts (junit.xml, coverage.xml) always uploaded
- Bandit JSON report always uploaded as artifact
- Adds docs/CIWorkflow.md with maintainer documentation
- Updates CONTRIBUTING.md with CI workflow table and link
Co-authored-by: christianlouis <361235+christianlouis@users.noreply.github.com>