FEAT(traefik): add per-application ingress managem

- Added ingress.yaml for code-server, kubernetes-dashboard, and umami
- Updated kustomization files to include ingress resources
- Migrated from centralized ingress management to per-app architecture

umami/kustomization.yaml

@@ -5,3 +5,4 @@ resources:
   # ArgoCD Application 리소스는 infrastructure/kustomization.yaml에서 관리
   # - argocd/umami.yaml
   - vault/umami-password.yaml
+  - ingress.yaml