feat(ui): 专业风UI改造 主色#275354 + Brand系统标题统一

- 全量替换游戏感Neo-Brutalist为政务专业风：圆角2-16px、薄灰边、柔阴影
- Tailwind主题：primary 10阶调色板 + Noto Sans SC主字体 + fade-in-up动画
- 全局CSS：浅灰F6F8F9背景 + 主色焦点环和滚动条 + card/chip工具类
- 品牌组件Brand.tsx：云图形截断防云盘旧字泄露 + 新标题组合
- 6基础组件 + 8页面：Layout深绿侧栏 Login卡片 Export去五色卡 Activities/Hours/Users 用户端Index/Dashboard
- 数据链路回归：u/2张三2h明细正确显示
- tsc无错误  vite build成功

client/src/pages/user/Dashboard.tsx

@@ -2,6 +2,7 @@ import { useEffect, useState } from 'react';
 import { useNavigate, useParams } from 'react-router-dom';
 import Button from '../../components/Button';
 import DataTable from '../../components/DataTable';
+import Brand from '../../components/Brand';
 import { usersApi, errMsg } from '../../api';
 import { formatDateRange } from '../../utils/export';
 import type { UserDetail } from '../../types';
@@ -31,54 +32,58 @@ export default function UserDashboard() {
   if (!data) return null;
 
   return (
-    <div className="min-h-screen bg-gray-50 px-4 py-6 md:py-10">
+    <div className="min-h-screen bg-paper px-4 py-6 md:py-10">
       <div className="max-w-5xl mx-auto">
-        <div className="flex justify-between items-center mb-5 flex-wrap gap-2">
-          <div className="flex items-start gap-2">
-            <IconClock size={28} className="mt-0.5 shrink-0" />
-            <h1 className="text-xl md:text-2xl font-black tracking-wide">个人义工时长总览</h1>
-          </div>
+        <div className="mb-5 flex items-center justify-between flex-wrap gap-2">
+          <Brand variant="dark" size="sm" showTitle={true} />
           <Button variant="secondary" onClick={() => navigate('/u')}><span className="inline-flex items-center gap-2"><IconArrowLeft size={18} />返回查询</span></Button>
         </div>
 
-        <div className="bg-white border-2 border-black p-5 mb-5">
+        <div className="mb-5 flex items-start gap-2 animate-fade-in-up">
+          <div className="shrink-0 p-2 bg-primary-50 text-primary-600 rounded-md mt-0.5">
+            <IconClock size={26} />
+          </div>
+          <h1 className="section-title mt-1">个人义工时长总览</h1>
+        </div>
+
+        <div className="card p-5 mb-5 animate-fade-in-up">
           <div className="grid grid-cols-2 md:grid-cols-4 gap-4">
             <div>
-              <div className="text-xs text-gray-500 mb-1">姓名</div>
-              <div className="text-lg font-bold">{data.name}</div>
+              <div className="muted mb-1">姓名</div>
+              <div className="text-lg font-semibold text-gray-800">{data.name}</div>
             </div>
             <div>
-              <div className="text-xs text-gray-500 mb-1">班级</div>
-              <div className="text-lg font-bold">{data.class || '—'}</div>
+              <div className="muted mb-1">班级</div>
+              <div className="text-lg font-semibold text-gray-800">{data.class || '—'}</div>
             </div>
             <div>
-              <div className="text-xs text-gray-500 mb-1">义工号</div>
-              <div className="text-lg font-bold">{data.volunteer_no || '—'}</div>
+              <div className="muted mb-1">义工号</div>
+              <div className="text-lg font-semibold text-gray-800">{data.volunteer_no || '—'}</div>
             </div>
             <div>
-              <div className="text-xs text-gray-500 mb-1">所属工作组</div>
-              <div className="text-lg font-bold">{data.group_name || '—'}</div>
+              <div className="muted mb-1">所属工作组</div>
+              <div className="text-lg font-semibold text-gray-800">{data.group_name || '—'}</div>
             </div>
           </div>
-          <div className="mt-5 pt-5 border-t-2 border-gray-200 grid grid-cols-2 gap-4">
-            <div className="bg-gray-50 border-2 border-gray-200 p-4">
-              <div className="text-xs text-gray-500 mb-1">累计义工时长</div>
-              <div className="text-2xl md:text-3xl font-black text-black">{Number(data.total_hours || 0).toFixed(2)} <span className="text-base font-bold text-gray-600">小时</span></div>
+          <div className="mt-5 pt-5 border-t border-gray-200 grid grid-cols-2 gap-4">
+            <div className="card p-4 bg-primary-50/50">
+              <div className="muted mb-1">累计义工时长</div>
+              <div className="text-2xl md:text-3xl font-semibold text-primary-600">{Number(data.total_hours || 0).toFixed(2)} <span className="text-base font-medium text-gray-600">小时</span></div>
             </div>
-            <div className="bg-gray-50 border-2 border-gray-200 p-4">
-              <div className="text-xs text-gray-500 mb-1">参与活动数</div>
-              <div className="text-2xl md:text-3xl font-black text-black">{data.activities.length} <span className="text-base font-bold text-gray-600">次</span></div>
+            <div className="card p-4">
+              <div className="muted mb-1">参与活动数</div>
+              <div className="text-2xl md:text-3xl font-semibold text-gray-800">{data.activities.length} <span className="text-base font-medium text-gray-600">次</span></div>
             </div>
           </div>
         </div>
 
-        <h2 className="font-bold text-lg mb-3">参与活动明细</h2>
+        <h2 className="font-semibold text-lg mb-3 text-gray-800">参与活动明细</h2>
         <DataTable
           id="user-activities-table"
           columns={[
-            { key: 'title', title: '活动名称', render: (r: any) => <span className="font-medium">{r.title}</span> },
+            { key: 'title', title: '活动名称', render: (r: any) => <span className="font-medium text-gray-800">{r.title}</span> },
             { key: 'time', title: '活动时间', render: (r: any) => formatDateRange(r.start_time, r.end_time) },
-            { key: 'hours', title: '时长（小时）', render: (r: any) => <span className="font-bold">{Number(r.hours || 0).toFixed(2)}</span> },
+            { key: 'hours', title: '时长（小时）', render: (r: any) => <span className="font-semibold text-primary-600">{Number(r.hours || 0).toFixed(2)}</span> },
             { key: 'remark', title: '备注', render: (r: any) => r.remark || '—' },
           ]}
           data={data.activities}