refactor(targets): unify queue/connectivity handling and coverage (#2953)

Co-authored-by: Claude Opus 4.7 <noreply@anthropic.com>
Co-authored-by: marshawcoco <marshawcoco@gmail.com>

crates/targets/src/domain.rs

@@ -0,0 +1,43 @@
+// Copyright 2024 RustFS Team
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+use crate::target::TargetType;
+use serde::{Deserialize, Serialize};
+
+/// Logical target domains supported by RustFS target plugins.
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, Serialize, Deserialize)]
+#[serde(rename_all = "snake_case")]
+pub enum TargetDomain {
+    Notify,
+    Audit,
+}
+
+impl TargetDomain {
+    #[inline]
+    pub fn runtime_target_type(self) -> TargetType {
+        match self {
+            TargetDomain::Notify => TargetType::NotifyEvent,
+            TargetDomain::Audit => TargetType::AuditLog,
+        }
+    }
+}
+
+impl From<TargetType> for TargetDomain {
+    fn from(value: TargetType) -> Self {
+        match value {
+            TargetType::NotifyEvent => TargetDomain::Notify,
+            TargetType::AuditLog => TargetDomain::Audit,
+        }
+    }
+}