Phase 8.13 — RKE2 upgrade to 1.36

Both clusters — the production cluster and the management cluster that runs ArgoCD and the other platform-level tooling — move onto RKE2 1.36, the current stable release line. That carries forward the underlying Kubernetes version along with the networking and control-plane components that ship with it.

This is routine maintenance rather than a feature change: staying on a current, supported release line is what keeps security patches and bug fixes flowing, and what keeps every other upgrade on the roadmap landing on solid ground.

What this phase does

• Upgrades both clusters to RKE2 1.36 through the platform's own rolling node-by-node process.
• Runs pre-flight checks beforehand and a post-upgrade health pass on every node afterwards.

Brief, scheduled disruption only — each node is drained and rejoined in turn, so the cluster as a whole stays up throughout.