Install valkey-operator (#365)

Makes the valkey-operator available in the cluster so a later change can replace the self-managed redis Deployment with a Valkey CR. This PR only installs the operator; it does not create any Valkey CR or touch existing apps.

Changes:
- Add `apps/base/valkey-operator-system/` (namespace `valkey-operator-system`, mirroring the cnpg-system pattern).
- Add `apps/overlays/au-syd1/valkey-operator-system/` which inflates the `valkey-operator` 0.5.0 Helm chart from the artifactapi virtual helm repo with `includeCRDs: true` (the chart ships CRDs in the Helm-native `crds/` dir, which `helm template` skips otherwise).
- Route the operator image through artifactapi: `artifactapi.k8s.syd1.au.unkin.net/ghcr/valkey-io/valkey-operator:v0.5.0`.
- Register `apps/overlays/*/valkey-operator-system` in the platform ApplicationSet. No AppProject change needed: the `*-system` destination and the virtual-helm sourceRepo already cover it (same as cnpg-system/cephrgw-system).

Depends on unkin/terraform-artifactapi#29 (adds the valkey helm remote + virtual member and allowlists the operator image). That PR must merge and apply before this one syncs, or the chart pull / image pull will 404/403.

Validated with `kustomize build --enable-helm` against the upstream chart (identical version/values): renders the Namespace, 2 CRDs, operator Deployment (image = the artifactapi ghcr path), RBAC, SA, and metrics Service, all in `valkey-operator-system`.

Reviewed-on: #365
Co-authored-by: unkin-agent <unkin-agent@unkin.net>
Co-committed-by: unkin-agent <unkin-agent@unkin.net>

apps/base/valkey-operator-system/kustomization.yaml

@@ -0,0 +1,6 @@
+---
+apiVersion: kustomize.config.k8s.io/v1beta1
+kind: Kustomization
+
+resources:
+  - namespace.yaml

apps/base/valkey-operator-system/namespace.yaml

@@ -0,0 +1,5 @@
+---
+apiVersion: v1
+kind: Namespace
+metadata:
+  name: valkey-operator-system

apps/overlays/au-syd1/valkey-operator-system/kustomization.yaml

@@ -0,0 +1,17 @@
+---
+apiVersion: kustomize.config.k8s.io/v1beta1
+kind: Kustomization
+
+resources:
+  - ../../../base/valkey-operator-system
+
+helmCharts:
+  - name: valkey-operator
+    repo: https://artifactapi.k8s.syd1.au.unkin.net/api/v1/virtual/helm
+    version: "0.5.0"
+    releaseName: valkey-operator
+    namespace: valkey-operator-system
+    valuesFile: values.yaml
+    # The chart ships CRDs in the Helm-native crds/ dir, which helm template
+    # skips unless CRDs are explicitly included.
+    includeCRDs: true

apps/overlays/au-syd1/valkey-operator-system/values.yaml

@@ -0,0 +1,14 @@
+image:
+  registry: artifactapi.k8s.syd1.au.unkin.net/ghcr
+  repository: valkey-io/valkey-operator
+  tag: v0.5.0
+
+replicaCount: 1
+
+resources:
+  limits:
+    cpu: 500m
+    memory: 256Mi
+  requests:
+    cpu: 10m
+    memory: 64Mi

argocd/applicationsets/platform.yaml

@@ -43,6 +43,7 @@ spec:
       - path: apps/overlays/*/reloader-system
       - path: apps/overlays/*/reposync
       - path: apps/overlays/*/traefik-system
+      - path: apps/overlays/*/valkey-operator-system
       - path: apps/overlays/*/vm-system
       - path: apps/overlays/*/vpa-system
       - path: apps/overlays/*/vault