Per review feedback: remove the self-hosted Renovate deployment
(kubernetes/code/renovate/* + root kustomization wiring) from this PR and
defer it to a follow-up. Keep the renovate.json config to merge now.
Also drop the postUpgradeTasks SOPS re-encrypt block: it depended on the
runner's boot.sh decrypt flow, and the hosted Mend app cannot run 'sops'
(allowedPostUpgradeCommands). SOPS handling returns with the deployment.
