feat(web): wire Home dashboard to real API data

Replace hardcoded placeholder values with live data fetched from
/users, /roles, /workflow/instances, and message store unread count.
Uses Promise.allSettled for resilient parallel loading.

apps/web/src/pages/Home.tsx

@@ -1,37 +1,97 @@
-import { Typography, Card, Row, Col, Statistic } from 'antd';
+import { useEffect, useState } from 'react';
+import { Typography, Card, Row, Col, Statistic, Spin } from 'antd';
 import {
   UserOutlined,
   TeamOutlined,
   FileTextOutlined,
   BellOutlined,
 } from '@ant-design/icons';
+import client from '../api/client';
+import { useMessageStore } from '../stores/message';
+
+interface DashboardStats {
+  userCount: number;
+  roleCount: number;
+  processInstanceCount: number;
+  unreadMessages: number;
+}
 
 export default function Home() {
+  const [stats, setStats] = useState<DashboardStats>({
+    userCount: 0,
+    roleCount: 0,
+    processInstanceCount: 0,
+    unreadMessages: 0,
+  });
+  const [loading, setLoading] = useState(true);
+  const { unreadCount, fetchUnreadCount } = useMessageStore();
+
+  useEffect(() => {
+    async function loadStats() {
+      setLoading(true);
+      try {
+        // 并行请求各模块统计数据
+        const [usersRes, rolesRes, instancesRes] = await Promise.allSettled([
+          client.get('/users', { params: { page: 1, page_size: 1 } }),
+          client.get('/roles', { params: { page: 1, page_size: 1 } }),
+          client.get('/workflow/instances', { params: { page: 1, page_size: 1 } }),
+        ]);
+
+        const extractTotal = (res: PromiseSettledResult<{ data: { data?: { total?: number } } }>) =>
+          res.status === 'fulfilled' ? (res.value.data?.data?.total ?? 0) : 0;
+
+        setStats({
+          userCount: extractTotal(usersRes),
+          roleCount: extractTotal(rolesRes),
+          processInstanceCount: extractTotal(instancesRes),
+          unreadMessages: unreadCount,
+        });
+      } catch {
+        // 静默处理，显示默认值
+      } finally {
+        setLoading(false);
+      }
+    }
+
+    fetchUnreadCount();
+    loadStats();
+  }, [fetchUnreadCount, unreadCount]);
+
   return (
     <div>
       <Typography.Title level={4}>工作台</Typography.Title>
+      <Spin spinning={loading}>
         <Row gutter={[16, 16]}>
           <Col xs={24} sm={12} md={6}>
             <Card>
-            <Statistic title="用户总数" value={0} prefix={<UserOutlined />} />
+              <Statistic title="用户总数" value={stats.userCount} prefix={<UserOutlined />} />
             </Card>
           </Col>
           <Col xs={24} sm={12} md={6}>
             <Card>
-            <Statistic title="角色数量" value={0} prefix={<TeamOutlined />} />
+              <Statistic title="角色数量" value={stats.roleCount} prefix={<TeamOutlined />} />
             </Card>
           </Col>
           <Col xs={24} sm={12} md={6}>
             <Card>
-            <Statistic title="流程实例" value={0} prefix={<FileTextOutlined />} />
+              <Statistic
+                title="流程实例"
+                value={stats.processInstanceCount}
+                prefix={<FileTextOutlined />}
+              />
             </Card>
           </Col>
           <Col xs={24} sm={12} md={6}>
             <Card>
-            <Statistic title="未读消息" value={0} prefix={<BellOutlined />} />
+              <Statistic
+                title="未读消息"
+                value={stats.unreadMessages}
+                prefix={<BellOutlined />}
+              />
             </Card>
           </Col>
         </Row>
+      </Spin>
     </div>
   );
 }