refac: DELETE /v1/user/{id}?expected_role_id=N, user.remove audit event, 409 target_role_not_found, GetAll returns its error, Own-scope visibility filter moved into repos, JSON tags removed from use-case types

internal/infrastructure/persistence/repositories/userRepository.go

@@ -52,6 +52,26 @@ func (u *UserRepository) Delete(id uint32) error {
 	return deleteOrNotFound(result, domainUser.ErrUserNotFound)
 }
 
+func (u *UserRepository) DeleteIfRole(id uint32, roleID uint32) error {
+	return u.db.Transaction(func(tx *gorm.DB) error {
+		result := tx.Where("id = ? AND role_id = ?", id, roleID).Delete(&entity.User{})
+		if result.Error != nil {
+			return result.Error
+		}
+		if result.RowsAffected > 0 {
+			return nil
+		}
+		var users int64
+		if err := tx.Model(&entity.User{}).Where("id = ?", id).Count(&users).Error; err != nil {
+			return err
+		}
+		if users == 0 {
+			return domainUser.ErrUserNotFound
+		}
+		return domainUser.ErrRoleChanged
+	})
+}
+
 func (u *UserRepository) GetAll() ([]domainUser.User, error) {
 	var users []entity.User
 	if err := u.db.Model(&entity.User{}).Find(&users).Error; err != nil {