Add user management page and technician picker for reassign

- New /admin/users page (admin only) for creating technicians,
  editing role/email, resetting passwords, deleting users
- AftersalesDetail reassign modal now uses a searchable Select
  populated from /api/users/assignable instead of raw user ID input
- Menu entry only shown to admins

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/pages/AftersalesDetail.tsx

@@ -23,12 +23,13 @@ import {
   StopOutlined,
   UserSwitchOutlined,
 } from '@ant-design/icons';
-import { aftersalesApi, authApi } from '@/services/api';
+import { aftersalesApi, authApi, usersApi } from '@/services/api';
 import type {
   AftersalesOrder,
   AftersalesServiceType,
   AftersalesWorkOrderStatus,
   UpdateAftersalesRequest,
+  User,
 } from '@/types';
 
 const SERVICE_TYPE_LABEL: Record<AftersalesServiceType, string> = {
@@ -81,6 +82,7 @@ function AftersalesDetailPage() {
 
   const [reassignModalVisible, setReassignModalVisible] = useState(false);
   const [reassignTechnicianId, setReassignTechnicianId] = useState<number | undefined>();
+  const [assignableUsers, setAssignableUsers] = useState<User[]>([]);
 
   const loadOrder = async () => {
     setLoading(true);
@@ -107,6 +109,18 @@ function AftersalesDetailPage() {
     // eslint-disable-next-line react-hooks/exhaustive-deps
   }, [serialNumber]);
 
+  const openReassign = async () => {
+    setReassignModalVisible(true);
+    if (assignableUsers.length === 0) {
+      try {
+        const users = await usersApi.assignable();
+        setAssignableUsers(users);
+      } catch (err: any) {
+        message.error(err?.response?.data?.message || err.message || '加载技术员列表失败');
+      }
+    }
+  };
+
   const handleSave = async (values: UpdateAftersalesRequest) => {
     if (!order) return;
     setSaving(true);
@@ -260,7 +274,7 @@ function AftersalesDetailPage() {
             </Button>
             {isAdmin && !isClosed && (
               <>
-                <Button icon={<UserSwitchOutlined />} onClick={() => setReassignModalVisible(true)}>
+                <Button icon={<UserSwitchOutlined />} onClick={openReassign}>
                   重新分配
                 </Button>
                 <Button danger icon={<StopOutlined />} onClick={handleForceClose}>
@@ -424,25 +438,28 @@ function AftersalesDetailPage() {
       <Modal
         title="重新分配技术员"
         open={reassignModalVisible}
-        onCancel={() => setReassignModalVisible(false)}
+        onCancel={() => {
+          setReassignModalVisible(false);
+          setReassignTechnicianId(undefined);
+        }}
         onOk={handleReassign}
         okText="确认"
         cancelText="取消"
       >
         <Form layout="vertical">
-          <Form.Item label="新技术员 ID" required>
-            <Input
-              type="number"
-              placeholder="请输入技术员的用户 ID"
+          <Form.Item label="选择技术员" required>
+            <Select
+              placeholder="请选择技术员或管理员"
               value={reassignTechnicianId}
-              onChange={(e) =>
-                setReassignTechnicianId(e.target.value ? Number(e.target.value) : undefined)
-              }
+              onChange={(v) => setReassignTechnicianId(v)}
+              showSearch
+              optionFilterProp="label"
+              options={assignableUsers.map((u) => ({
+                value: u.id,
+                label: `${u.name}（${u.username}）${u.role === 'admin' ? ' · 管理员' : ' · 技术员'}`,
+              }))}
             />
           </Form.Item>
-          <p style={{ color: '#888', fontSize: 12 }}>
-            后续会在用户管理页提供技术员列表选择，目前先输入 ID。
-          </p>
         </Form>
       </Modal>
     </div>