4 (Logical Infrastructure stack) complete**: Continuous delivery pipeline fully migrated from kustom

Tracking ticket for a line in release 5.1.46.3 that shipped without one.

Phase 4 (Logical Infrastructure stack) complete: Continuous delivery pipeline fully migrated from kustomize to helm; ArgoCD Image Updater and Rollouts deployed across the cluster fleet. All kubernetes infrastructure-layer applications are in place.

Created retroactively so every changelog line has a ticket a reader can follow.