feat(imports): 导入向导兼容旧版工作簿并完善执行/预览

- 新增 xls 工作簿回退解析与测试
- 执行/预览/权限校验逻辑完善

apps/server/src/imports/imports.access.spec.ts

@@ -0,0 +1,37 @@
+import { ForbiddenException } from '@nestjs/common';
+import { assertStepPermission, permittedStepKeys } from './imports.access';
+
+describe('permittedStepKeys', () => {
+  it('超级管理员拥有全部导入阶段', () => {
+    expect(
+      permittedStepKeys({ id: 1, permissions: [], isSuperAdmin: true }),
+    ).toEqual(['students', 'rooms', 'checkins', 'transfers']);
+  });
+
+  it('按细分权限计算可提交阶段', () => {
+    expect(
+      permittedStepKeys({
+        id: 1,
+        permissions: ['student:import', 'room:edit', 'occupancy:checkin'],
+        isSuperAdmin: false,
+      }),
+    ).toEqual(['students', 'rooms', 'checkins']);
+  });
+
+  it('无导入权限时仅返回空数组', () => {
+    expect(
+      permittedStepKeys({ id: 1, permissions: ['ai:chat:use'], isSuperAdmin: false }),
+    ).toEqual([]);
+  });
+});
+
+describe('assertStepPermission', () => {
+  it('无对应细分权限时拒绝提交', () => {
+    expect(() =>
+      assertStepPermission(
+        { id: 1, permissions: ['ai:chat:use'], isSuperAdmin: false },
+        'transfers',
+      ),
+    ).toThrow(ForbiddenException);
+  });
+});