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/prometheus-node-exporter/4.55.0/templates/endpoints.yaml

@@ -0,0 +1,18 @@
+{{- if .Values.endpoints }}
+apiVersion: v1
+kind: Endpoints
+metadata:
+  name: {{ include "prometheus-node-exporter.fullname" . }}
+  namespace: {{ include "prometheus-node-exporter.namespace" . }}
+  labels:
+    {{- include "prometheus-node-exporter.labels" . | nindent 4 }}
+subsets:
+  - addresses:
+      {{- range .Values.endpoints }}
+      - ip: {{ . }}
+      {{- end }}
+    ports:
+      - name: {{ .Values.service.portName }}
+        port: 9100
+        protocol: TCP
+{{- end }}