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-cluster/0.43.0/templates/extra-secrets.yaml

@@ -0,0 +1,21 @@
+{{- if .Values.extraSecrets }}
+{{- $ctx := dict "helm" . }}
+{{- range .Values.extraSecrets }}
+---
+apiVersion: v1
+kind: Secret
+metadata:
+  {{- with .annotations }}
+  annotations: {{ toYaml . | nindent 4 }}
+  {{- end }}
+  {{- $_ := set $ctx "extraLabels" .labels }}
+  labels: {{ include "vm.metaLabels" $ctx | nindent 4 }}
+  {{- $_ := unset $ctx "extraLabels" }}
+  name: {{ .name }}
+  namespace: {{ include "vm.namespace" $ }}
+type: Opaque
+{{- with .data }}
+data: {{- tpl . $ | nindent 2 }}
+{{- end }}
+{{- end }}
+{{- end }}