fix: resolve 5 review findings

Critical 1: Remove broken '钉钉绑定' tab (IntegConfig) — deleted /rbac/user-ding-mappings calls
Critical 2: Fix decorator placement in CreateClassDto — @IsOptional @IsArray restored to teachers
Important 1: Restore sync.service.spec.ts from 1fa3363, strip importDingTalkUsers tests
Important 2: Fix N+1 in batchImportStudents — batched find/save with In() operator
Important 3: Add migrate-student-ding-mapping.sql

apps/admin/src/pages/IntegrationConfig/index.tsx

@@ -1,7 +1,7 @@
 import React, { useEffect, useState, useMemo, useCallback } from 'react';
 import {
   Card, Form, Input, Button, Space, message, Spin, Switch, Alert, Descriptions, Tag,
-  Tabs, Drawer, Tree, Select, TreeSelect, Modal, DatePicker, InputNumber, Table, Popconfirm,
+  Tabs, Drawer, Tree, Select, TreeSelect, Modal, DatePicker, InputNumber,
   Row, Col, List,
 } from 'antd';
 import {
@@ -79,12 +79,6 @@ const IntegrationConfigPage: React.FC = () => {
   const [classForm] = Form.useForm();
   const [classModalOpen, setClassModalOpen] = useState(false);
 
-  // ── DingTalk Bindings Tab ──
-  const [bindings, setBindings] = useState<Array<{ id: number; userId: number; dingUserId: string; dingName: string | null; dingMobile: string | null; user: { id: number; username: string; name: string } }>>([]);
-  const [unboundUsers, setUnboundUsers] = useState<Array<{ id: number; username: string; name: string }>>([]);
-  const [bindModalOpen, setBindModalOpen] = useState(false);
-  const [bindForm] = Form.useForm<{ userId: number; dingUserId: string; dingName?: string; dingMobile?: string }>();
-  const [bindSubmitting, setBindSubmitting] = useState(false);
 
   const fetchConfig = async () => {
     setLoading(true);
@@ -141,54 +135,6 @@ const IntegrationConfigPage: React.FC = () => {
     }
   };
 
-  const fetchBindings = useCallback(async () => {
-    try {
-      const res = await api.get<typeof bindings>('/rbac/user-ding-mappings');
-      setBindings(res);
-    } catch { /* ignore */ }
-  }, []);
-
-  const fetchUnboundUsers = useCallback(async () => {
-    try {
-      const res = await api.get<typeof unboundUsers>('/rbac/user-ding-mappings/unbound-users');
-      setUnboundUsers(res);
-    } catch { /* ignore */ }
-  }, []);
-
-  useEffect(() => {
-    fetchBindings();
-  }, [fetchBindings]);
-
-  const handleBindSubmit = async () => {
-    try {
-      const values = await bindForm.validateFields();
-      setBindSubmitting(true);
-      await api.post('/rbac/user-ding-mappings', values);
-      message.success('绑定成功');
-      setBindModalOpen(false);
-      bindForm.resetFields();
-      fetchBindings();
-    } catch (e: unknown) {
-      const err = e as { message?: string };
-      if (err.message) message.error(err.message);
-    } finally {
-      setBindSubmitting(false);
-    }
-  };
-
-  const handleUnbind = async (id: number) => {
-    Modal.confirm({
-      title: '确认解绑？',
-      content: '解绑后该用户将无法自动匹配钉钉考勤。',
-      okText: '解绑',
-      okType: 'danger',
-      onOk: async () => {
-        await api.delete(`/rbac/user-ding-mappings/${id}`);
-        message.success('已解绑');
-        fetchBindings();
-      },
-    });
-  };
 
   const loadDeptTree = async () => {
     try {
@@ -503,81 +449,6 @@ const IntegrationConfigPage: React.FC = () => {
         </Spin>
       ),
     },
-    {
-      key: 'bindings',
-      label: '钉钉绑定',
-      children: (
-        <div>
-          <div style={{ marginBottom: 16, display: 'flex', justifyContent: 'space-between', alignItems: 'center' }}>
-            <span style={{ fontWeight: 500 }}>用户绑定管理</span>
-            <Button
-              type="primary"
-              icon={<PlusOutlined />}
-              onClick={async () => {
-                await fetchUnboundUsers();
-                setBindModalOpen(true);
-              }}
-            >
-              新增绑定
-            </Button>
-          </div>
-          <Table
-            dataSource={bindings}
-            rowKey="id"
-            columns={[
-              {
-                title: '本地用户',
-                key: 'user',
-                render: (_: unknown, r: typeof bindings[number]) => (
-                  <Space>
-                    <span>{r.user?.name || '-'}</span>
-                    <Tag>{r.user?.username}</Tag>
-                  </Space>
-                ),
-              },
-              { title: '钉钉用户ID', dataIndex: 'dingUserId', key: 'dingUserId' },
-              { title: '钉钉名称', dataIndex: 'dingName', key: 'dingName', render: (v: string | null) => v || '-' },
-              { title: '钉钉手机', dataIndex: 'dingMobile', key: 'dingMobile', render: (v: string | null) => v || '-' },
-              {
-                title: '操作',
-                key: 'actions',
-                render: (_: unknown, r: typeof bindings[number]) => (
-                  <Popconfirm title="确认解绑？" onConfirm={() => handleUnbind(r.id)} okText="解绑" okType="danger">
-                    <Button size="small" danger>解绑</Button>
-                  </Popconfirm>
-                ),
-              },
-            ]}
-            pagination={{ pageSize: 20 }}
-            locale={{ emptyText: '暂无绑定记录' }}
-          />
-          <Modal
-            title="新增钉钉绑定"
-            open={bindModalOpen}
-            onOk={handleBindSubmit}
-            onCancel={() => { setBindModalOpen(false); bindForm.resetFields(); }}
-            confirmLoading={bindSubmitting}
-          >
-            <Form form={bindForm} layout="vertical">
-              <Form.Item name="userId" label="本地用户" rules={[{ required: true, message: '请选择用户' }]}>
-                <Select
-                  showSearch
-                  placeholder="搜索本地用户"
-                  optionFilterProp="label"
-                  options={unboundUsers.map((u) => ({
-                    value: u.id,
-                    label: `${u.name || u.username} (${u.username})`,
-                  }))}
-                />
-              </Form.Item>
-              <Form.Item name="dingUserId" label="钉钉用户ID" rules={[{ required: true, message: '请输入钉钉用户ID' }]} extra="在钉钉管理后台 → 通讯录 → 成员详情 中可查看">
-                <Input placeholder="如: manager123" />
-              </Form.Item>
-            </Form>
-          </Modal>
-        </div>
-      ),
-    },
     ...syncTabItems,
   ];