feat(zone): add zone management api and legacy importer

internal/apps/openflare/zone/errs.go

@@ -0,0 +1,16 @@
+// Copyright 2026 Arctel.net
+// SPDX-License-Identifier: Apache-2.0
+
+package zone
+
+const (
+	errZoneDomainRequired        = "域名不能为空"
+	errZoneRootInvalid           = "zone 必须是有效的注册根域"
+	errDomainInvalid             = "域名格式不合法"
+	errDomainWildcardUnsupported = "不支持通配符域名"
+	errDomainOutsideZone         = "域名不属于该 Zone"
+	errZoneNotFound              = "Zone 不存在"
+	errDomainNotFound            = "域名不存在"
+	errDomainExists              = "域名已存在"
+	errCertificateNotFound       = "所选证书不存在"
+)