fix(用户管理): 删除用户时级联清理服务端密钥，修已删账号留下孤儿密钥行

biz_user_api_secret 按 uid 绑定且无外键，删除用户后密钥/代理配置成为无主行
（生产已出现 5 条孤儿）。deleteUser 内同步调用 adminClearByUser 并纳入同一事务，
删除失败（行不存在）时不触碰密钥。

backend-java/src/main/java/com/nanri/aiimage/modules/admin/service/AdminUserService.java

@@ -15,7 +15,9 @@ import com.nanri.aiimage.modules.permission.mapper.AdminUserMapper;
 import com.nanri.aiimage.modules.permission.model.dto.UserColumnPermissionUpdateRequest;
 import com.nanri.aiimage.modules.permission.model.entity.AdminUserEntity;
 import com.nanri.aiimage.modules.permission.service.PermissionMenuService;
+import com.nanri.aiimage.modules.usersecret.service.UserApiSecretService;
 import lombok.RequiredArgsConstructor;
+import lombok.extern.slf4j.Slf4j;
 import org.springframework.dao.DuplicateKeyException;
 import org.springframework.stereotype.Service;
 import org.springframework.transaction.annotation.Transactional;
@@ -32,6 +34,7 @@ import java.util.stream.Collectors;
 
 @Service
 @RequiredArgsConstructor
+@Slf4j
 public class AdminUserService {
 
     private static final DateTimeFormatter CREATED_AT_FORMATTER = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm");
@@ -40,6 +43,7 @@ public class AdminUserService {
     private final WerkzeugPasswordEncoder passwordEncoder;
     private final AdminAuthSupport adminAuthSupport;
     private final PermissionMenuService permissionMenuService;
+    private final UserApiSecretService userApiSecretService;
 
     public AdminUserListVo listUsers(AdminUserEntity currentUser, Integer page, Integer pageSize,
                                      String username, Long createdById, String roleFilter) {
@@ -271,6 +275,8 @@ public class AdminUserService {
                 operator, userId, permissionRequest, menuType, false);
     }
 
+    /** 删除用户并级联清理其服务端密钥；不清理会留下无主密钥行（biz_user_api_secret 按 uid 绑定，无外键）。 */
+    @Transactional
     public void deleteUser(AdminUserEntity currentUser, Long uid) {
         String role = adminAuthSupport.currentRole(currentUser);
         if (role == null) {
@@ -297,6 +303,8 @@ public class AdminUserService {
         if (affected == 0) {
             throw new BusinessException("用户不存在");
         }
+        int secretRows = userApiSecretService.adminClearByUser(uid);
+        log.info("[admin-user] 用户已删除 uid={} 级联清理密钥行={}", uid, secretRows);
     }
 
     private Map<Long, String> loadCreatorMap(List<AdminUserEntity> rows) {