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/alertmanager/1.37.0/templates/vpa.yaml

@@ -0,0 +1,26 @@
+{{- if .Values.verticalPodAutoscaler.enabled }}
+apiVersion: autoscaling.k8s.io/v1
+kind: VerticalPodAutoscaler
+metadata:
+  name: {{ include "alertmanager.fullname" . }}
+  namespace: {{ .Release.Namespace }}
+spec:
+  {{- if .Values.verticalPodAutoscaler.recommenders }}
+  recommenders:
+    {{- range .Values.verticalPodAutoscaler.recommenders }}
+    - name: {{ .name }}
+    {{- end }}
+  {{- end }}
+  targetRef:
+    apiVersion: apps/v1
+    kind: StatefulSet
+    name: {{ include "alertmanager.fullname" . }}
+  {{- if .Values.verticalPodAutoscaler.updatePolicy }}
+  updatePolicy:
+    {{- toYaml .Values.verticalPodAutoscaler.updatePolicy | nindent 4 }}
+  {{- end }}
+  {{- if .Values.verticalPodAutoscaler.resourcePolicy }}
+  resourcePolicy:
+    {{- toYaml .Values.verticalPodAutoscaler.resourcePolicy | nindent 4 }}
+  {{- end }}
+{{- end }}