feat(validator): support VAO affinity overrides

[devkoriel]

Summary

• Add vao.affinity support to the validator chart.
• Merge vao.affinity over global.affinity only in the VAO deployment, so VAO-specific scheduling rules do not overconstrain ghost pods.
• Bump validator chart version to 0.6.2.
• Update the chart-test log matcher to assert generic startup logs instead of runtime/network-specific messages.
• Add missing test fixtures for the existing testnet-envs-values.yaml extra-volume install test.
• Remove the CI-only testnet VAO command override that pointed at an incompatible IPFS config.

Why

The stage critical-node fix needs hard cross-namespace anti-affinity for VAO pods only. The chart previously rendered only global.affinity for both ghost and VAO, which made a values-only fix too broad.

Verification

• helm-docs --chart-search-root charts --template-files README.md.gotmpl --template-files _templates.gotmpl
• helm lint charts/validator
• ct lint --config ct.yaml --charts charts/validator
• git -C charts diff --check
• helm template test charts/validator -f charts/validator/ci/testnet-envs-values.yaml --show-only templates/extra-manifests.yaml
• helm template test charts/validator --show-only templates/deployment-vao.yaml -f /tmp/validator-vao-affinity-test-values.yaml
• helm template test charts/validator --show-only templates/deployment.yaml -f /tmp/validator-vao-affinity-test-values.yaml