perf: Q3 N+1 查询优化 — user_service 和 plugin_service

- user_service::list() 循环内单查询改为 fetch_batch_user_role_resps 批量查询
- plugin_service::list() 循环内单查询改为 find_batch_plugin_entities 批量查询
- RoleResp 和 PluginEntityResp 添加 Clone derive

crates/erp-auth/src/dto.rs

@@ -73,7 +73,7 @@ pub struct UpdateUserReq {
 
 // --- Role DTOs ---
 
-#[derive(Debug, Serialize, ToSchema)]
+#[derive(Debug, Clone, Serialize, ToSchema)]
 pub struct RoleResp {
     pub id: Uuid,
     pub name: String,