refactor(backend): rename OpenFlare directory to lowercase openflare

backend/openflare/plugins/server/domain/fleet/flared/errs.go

@@ -0,0 +1,10 @@
+// Copyright 2026 Arctel.net
+// SPDX-License-Identifier: Apache-2.0
+
+// Package flared defines shared error messages for tunnel client operations.
+package flared
+
+const (
+	errTunnelTokenInvalid     = "无权进行此操作，Tunnel Token 无效" //nolint:gosec // false positive: this is an error message, not hardcoded credentials
+	errTunnelNodeTypeMismatch = "此节点不是 TunnelClient 类型"
+)