FEAT(velero): Add Velero, Falco,

- and CNPG infrastructure components
Add three critical infrastructure components via GitOps:

- Velero: Backup and disaster recovery solution
  - Configured with Minio S3 backend
  - Daily full cluster backups (30-day retention)
  - Hourly backups for critical namespaces (7-day retention)
  - Credentials managed via External Secrets from Vault

- Falco: Runtime security monitoring
  - eBPF-based threat detection
  - Custom rules for container security
  - Falcosidekick for alert forwarding
  - Prometheus metrics enabled

- CNPG (CloudNativePG): PostgreSQL operator
  - Kubernetes-native PostgreSQL management
  - Automated failover and backups
  - Will replace Bitnami PostgreSQL

All components follow existing GitOps patterns:
- Helm charts deployed via ArgoCD
- Values managed in Git
- Automated sync with selfHeal enabled

velero/kustomization.yaml

@@ -0,0 +1,9 @@
+apiVersion: kustomize.config.k8s.io/v1beta1
+kind: Kustomization
+
+resources:
+  # ArgoCD Application 리소스는 root kustomization.yaml에서 관리
+  # - argocd/velero.yaml
+
+  # Velero credentials from Vault
+  - external-secret.yaml