refactor(plugins): restructure admin and message_gateway into standard layered sub-packages

backend/plugins/domain/user/errs.go

@@ -3,6 +3,7 @@
 
 package user
 
+// HTTP 响应错误文案
 const (
 	errInvalidParams = "无效的请求参数"
 	errUserNotFound  = "用户不存在"
@@ -11,5 +12,32 @@ const (
 	//nolint:gosec // error message, not hardcoded credentials
 	errOldPasswordIncorrect = "原密码不正确"
 	//nolint:gosec // error message, not hardcoded credentials
-	errTokenNotFound = "访问令牌不存在"
+	errTokenNotFound    = "访问令牌不存在"
+	errCreateUserFailed = "创建用户失败: "
+	//nolint:gosec // error message, not hardcoded credentials
+	errCreateTokenFailed = "创建令牌失败"
+	//nolint:gosec // error message, not hardcoded credentials
+	errPasswordEncryptFailed = "密码加密失败"
+	//nolint:gosec // error message, not hardcoded credentials
+	errPasswordUpdateFailed = "密码更新失败"
+	//nolint:gosec // error message, not hardcoded credentials
+	errPasswordEmpty = "password cannot be empty"
+)
+
+// Service 层业务校验错误文案，取值被上游插件按字符串精确匹配消费，禁止改写
+const (
+	errUsernameEmpty        = "用户名不能为空"
+	errEmailEmpty           = "邮箱不能为空"
+	errUsernameTaken        = "用户名已被使用"
+	errEmailTaken           = "邮箱已被使用"
+	errCannotRevokeSelf     = "不能取消自己的管理员权限"
+	errAdminCannotDisable   = "管理员账号无法被禁用"
+	errAdminCannotDelete    = "管理员账号无法被删除"
+	errCannotDeleteSelf     = "不能删除当前登录用户"
+	errServiceUsernameEmpty = "user: username cannot be empty"
+	//nolint:gosec // error message, not hardcoded credentials
+	errServiceOldPasswordIncorrect = "user: incorrect old password"
+	//nolint:gosec // error message, not hardcoded credentials
+	errServicePasswordTooShort = "密码长度至少为 8 位"
+	errUniqueUsernameFailed    = "failed to generate unique username"
 )