task-58(账号/权限页面): 实现同级菜单排序交互

menu-manage-model.ts 增 siblingOrderAfterMove 同级内上下移(越界/缺失原序)；menu-manage-api.ts
增 reorderMenus POST /api/admin/column/reorder({ordered_ids})；MenusPage 每行上移/下移按钮
按同级组计算新顺序并提交后刷新。8 用例全过，427 单测 + build 绿。

admin-frontend-vue/src/pages/account/menu-manage-model.ts

@@ -177,6 +177,19 @@ export function menuDeleteReason(node: MenuManageNode | null | undefined): strin
   return undefined
 }
 
+/** 同级拖拽/上下移：把 targetId 移动 dir 位（±1），返回新的同级 id 顺序；越界/缺失则原序。 */
+export function siblingOrderAfterMove(group: number[], targetId: number, dir: number): number[] {
+  if (!Array.isArray(group) || group.length === 0) return []
+  const next = [...group]
+  const idx = next.indexOf(targetId)
+  if (idx < 0) return next
+  const to = idx + (dir === -1 || dir === 1 ? dir : 0)
+  if (to < 0 || to >= next.length) return next
+  const [moved] = next.splice(idx, 1)
+  next.splice(to, 0, moved)
+  return next
+}
+
 /** 新建/编辑表单空值工厂：默认菜单类型为 admin、排序 0、根父节点。 */
 export function emptyMenuManageForm(): MenuManageForm {
   return { name: '', columnKey: '', parentId: null, menuType: ADMIN_MENU_TYPE, routePath: '', sortOrder: 0 }