添加getAllChildDeptIds方法获取所有子部门ID

backend/src/main/java/com/designhub/service/DepartmentService.java

@@ -592,6 +592,30 @@ public class DepartmentService {
         return children;
     }
     
+    /**
+     * 获取部门的所有子部门ID（递归）
+     */
+    public List<Long> getAllChildDeptIds(Long deptId) {
+        List<Long> result = new ArrayList<>();
+        if (deptId == null) {
+            return result;
+        }
+        
+        // 查找直接子部门
+        List<Department> children = departmentMapper.selectList(
+            new LambdaQueryWrapper<Department>()
+                .eq(Department::getParentId, deptId)
+        );
+        
+        // 递归获取所有子部门
+        for (Department child : children) {
+            result.add(child.getId());
+            result.addAll(getAllChildDeptIds(child.getId()));
+        }
+        
+        return result;
+    }
+    
     /**
      * 检查用户是否为任何部门的负责人
      */