[EPIC] Helm Chart Support for Substrate Base Installation #3170

Tracks Helm Chart Workstream in Extensible Install

Goal

Each release publishes Helm charts to GHCR (OCI), generated from the rendered install, so Helm is a release artifact and not a second hand-maintained copy of the install:

• agent-substrate-crds
• one agent-substrate-<stage> chart per upgrade step of the version skew policy.
• agent-substrate, which depends on every stage chart, for fresh installs

General Requirements

• Generate charts from the rendered install rather than maintaining templates by hand ([FEATURE] Generate per-stage Helm charts and an install chart from the rendered release #3682):
  • one chart per upgrade step;
  • an install chart that depends on all of them;
  • a separate CRD chart, so CRDs upgrade ([FEATURE] Separate agent-substrate-crds chart #3684).
• Values schema generated from ate-setup's settings registry, so Helm validates values the same way ([FEATURE] Generate values.schema.json from ate-setup's settings registry #3683; value paths in [FEATURE] Base Helm Values for Installers #3186).
• Bootstrap runs as Helm hooks that are safe when Argo CD reruns them on every sync ([FEATURE] Run the install bootstrap as Helm hooks #3685).
• Publish all charts to GHCR (OCI) on each release ([FEATURE] Publish Helm charts to GHCR on each release #3686).
• CI installs, upgrades, and rolls back the charts on kind in the version skew policy's order ([FEATURE] Helm chart CI on kind: install, staged upgrade, rollback, repeated sync #3687).

Related: #79 (original Helm request, sub-issue), #3692 (Helm sizing values, under #3165).

Parent: #3158