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/custom-values.yaml

@@ -0,0 +1,18 @@
+# =============================================================================
+# prometheus-node-exporter — PaaSup 커스텀 오버라이드
+# 차트: prometheus-community/prometheus-node-exporter
+# 역할: 노드 시스템 메트릭(node_*) 노출 (DaemonSet)
+# 수집: vmagent가 monitoring 네임스페이스에서 스크레이핑 (job: node-exporter)
+# =============================================================================
+
+# 모든 노드(컨트롤플레인 포함)에 배치
+tolerations:
+  - operator: Exists
+
+resources:
+  requests:
+    cpu: 10m
+    memory: 32Mi
+  limits:
+    cpu: 100m
+    memory: 64Mi