Helm release checker

Changes under deployment/helm/charts/onyx/ or deployment/helm/charts/onyx-cnpg-crds/ require updates in deployment/helm/charts/onyx/Chart.yaml:

Increase version above the version on origin/main.
Update the release descriptions under annotations.artifacthub.io/changes. Describe the chart changes for users. Keep the general chart description unchanged unless the chart's purpose changes.

The helm-release pre-commit hook checks both requirements. Agent stop hooks also run pre-commit. CI uses the same check for chart pull requests. The check includes deletions and all files inside both chart directories. Changes to deployment/helm/README.md or deployment/helm/dev/ alone do not require a chart release.

Run git fetch origin main to refresh the local release baseline, then run pre-commit run helm-release --all-files. One update covers all commits in a branch. Release branches and application release tag builds do not publish charts and are exempt.

Run the regression tests from the repository root:

uv run --no-project --with PyYAML==6.0.3 --with semver==3.0.4 \
  python -m unittest discover -s tools/helm -v

The Helm Chart Version Check workflow also runs these tests when the checker, its workflow, the pre-commit configuration, or chart files change.