feat: complete E2E deployment flow with storage layered config and values template versioning

- Instance deployment: charts browser, deploy modal, instances list
- Values Template version management (create/history/rollback)
- Storage layered config (cluster > workspace > shared priority)
- Cluster credential decryptIfNeeded for mixed encrypted/plaintext kubeconfig
- YAML syntax validation (client-side + server-side warning)
- Frontend: charts, instances, storage, templates, admin pages
- Backend: storage service, instance service, cluster service, helm client
- Multi-Tenant Kubeconfig.md: added by user

backend/internal/adapter/input/http/dto/converter.go

@@ -76,6 +76,7 @@ func WorkspaceDTOFromEntity(workspace *entity.Workspace) *WorkspaceDTO {
 	return &WorkspaceDTO{
 		ID:          workspace.ID,
 		Name:        workspace.Name,
+		ClusterIDs:  workspace.ClusterIDs,
 		Description: workspace.Description,
 		CreatedBy:   workspace.CreatedBy,
 		CreatedAt:   workspace.CreatedAt,