REFACTOR(repo): restructure infra folder structure

- Remove argocd/, helm-values/, ingress/ subdirectories
- Move files to parent directory with standardized names
- Add namespace.yaml to all apps with Goldilocks labels
- Preserve vault/ subdirectories (falco, velero)
- Update main kustomization.yaml to reference argocd.yaml files directly
- Comment out argocd.yaml in each app's kustomization.yaml to prevent
  circular reference

Applications restructured:
- cert-manager (2 ArgoCD apps)
- external-secrets
- reloader
- vault (2 ArgoCD apps)
- velero (2 ArgoCD apps)
- falco
- cnpg
- haproxy
- metallb
- vpa
- argocd

velero/kustomization.yaml

@@ -2,10 +2,12 @@ apiVersion: kustomize.config.k8s.io/v1beta1
 kind: Kustomization
 
 resources:
-  # ArgoCD Application 리소스는 root kustomization.yaml에서 관리
-  # - argocd/velero.yaml
+  # argocd.yaml files은 수동으로 관리 (순환 참조 방지)
+  # - argocd-velero.yaml
+  # - argocd-ui.yaml
+  - namespace.yaml
 
   # Velero credentials from Vault
   - external-secret.yaml
   - vault/velero-ui-secret.yaml
-  - ingress/velero-ui-ingress.yaml
+  - ingress.yaml