Add VictoriaMetrics observability stack + sync catalog for monitoring test

- VM stack 10 charts: victoria-metrics-cluster/auth, victoria-logs-cluster,
  victoria-metrics-agent/alert, opentelemetry-collector, kube-state-metrics,
  prometheus-node-exporter, alertmanager, perses (JWT/OIDC, Infisical-ready)
- ArgoCD ApplicationSet (syncWave) + per-chart dip-values overlays
- doc/victoria-metrics-architecture.md, define-chart-resources updates
- includes pending working-tree changes (mlflow, kubeflow, apisix, CLAUDE.md)

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

manifests/helm/victoria-metrics-agent/0.40.0/templates/hpa.yaml

@@ -0,0 +1,25 @@
+{{- $hpa := .Values.horizontalPodAutoscaler }}
+{{- if $hpa.enabled }}
+{{- $ctx := dict "helm" . }}
+{{- $fullname := include "vm.plain.fullname" $ctx }}
+{{- $ns := include "vm.namespace" $ctx }}
+apiVersion: autoscaling/v2
+kind: HorizontalPodAutoscaler
+metadata:
+  {{- $_ := set $ctx "extraLabels" .Values.extraLabels }}
+  labels: {{ include "vm.labels" $ctx | nindent 4 }}
+  {{- $_ := unset $ctx "extraLabels" }}
+  name: {{ $fullname }}
+  namespace: {{ $ns }}
+spec:
+  maxReplicas: {{ $hpa.maxReplicas }}
+  minReplicas: {{ $hpa.minReplicas }}
+  scaleTargetRef:
+    apiVersion: apps/v1
+    kind: {{ title .Values.mode }}
+    name: {{ $fullname }}
+  metrics: {{ toYaml $hpa.metrics | nindent 4 }}
+  {{- with $hpa.behavior }}
+  behavior: {{ toYaml . | nindent 4 }}
+  {{- end -}}
+{{- end -}}