refactor: 页眉由 App 统一注入（ScreenLayout），三页共用一致页眉

- 新增 ScreenLayout 布局路由：注入共享 PageHeader + 全局左右键循环导航
- PageHeader 无 props，按路由自动识别状态（数据实时/3D 实时/媒体播放）
- DataScreen / DigitalTwin / MediaScreen 移除各自页眉，避免重复
- 页脚按页面按需保留（数据大屏 + 媒体轮播，数字孪生无）
- 管理后台不参与导航循环；旧 /screen2 路由移除
- 补齐 MediaScreen 音量/播放/翻页图标与浅色主题样式

src/components/Icons.jsx

@@ -9,6 +9,7 @@ import {
   Check, Gauge, Cpu, Server, Database, Sparkles, Bulb, Settings,
   Heart, Pill, Dna, Microscope, Atom, MapPin, Flag, Award, Medal,
   History, Drone, Plane, Rocket, Satellite, Wallet, UserPlus, Activity,
+  Volume, VolumeOff, ChevronLeft, ChevronRight, PlayerPlay, PlayerPause,
 } from '@appica/icons-react';
 
 /* 名称 → 图标组件映射（推荐的调用方式：icon="bolt"） */
@@ -64,6 +65,14 @@ const NAME_MAP = {
   wallet: Wallet,
   'user-plus': UserPlus,
   activity: Activity,
+  volume: Volume,
+  'volume-off': VolumeOff,
+  'chevron-left': ChevronLeft,
+  'chevron-right': ChevronRight,
+  'player-play': PlayerPlay,
+  'player-pause': PlayerPause,
+  play: PlayerPlay,
+  pause: PlayerPause,
 };
 
 /**
@@ -95,4 +104,5 @@ export {
   Check, Gauge, Cpu, Server, Database, Sparkles, Bulb, Settings,
   Heart, Pill, Dna, Microscope, Atom, MapPin, Flag, Award, Medal,
   History, Drone, Plane, Rocket, Satellite, Wallet, UserPlus, Activity,
+  Volume, VolumeOff, ChevronLeft, ChevronRight, PlayerPlay, PlayerPause,
 };

src/components/ParkOverviewStrip.jsx

@@ -0,0 +1,35 @@
+import Icon from './Icons';
+import { fmtInt, fmtWan } from '../utils/parkData';
+
+/* =========================================================
+   园区概览页脚（共享）—— 数据大屏 / 媒体播放页底部保持一致
+   ========================================================= */
+
+export default function ParkOverviewStrip({ d }) {
+  const chips = [
+    { icon: 'building', label: '在园项目', value: `${d.projects.inPark} 家` },
+    { icon: 'users', label: '带动就业', value: `${fmtInt(d.jobs.total)} 人` },
+    { icon: 'coin', label: '累计营收', value: `${fmtWan(d.revenue.total)} 元` },
+    { icon: 'factory', label: '高新技术企业', value: '32 家' },
+    { icon: 'flask', label: '省级以上重点研发', value: '18 项' },
+    { icon: 'trophy', label: '创业大赛奖项', value: '47 项' },
+    { icon: 'diamond', label: '孵化企业估值', value: '5.2 亿元' },
+    { icon: 'map-pin', label: '园区面积', value: '1.2 万㎡' },
+    { icon: 'graduation', label: '创业导师', value: '58 位' },
+    { icon: 'chart-line', label: '累计孵化企业', value: `${d.projects.cum} 家` },
+  ];
+  return (
+    <footer className="bd-strip">
+      <div className="bd-strip-title"><Icon name="map-pin" size={14} /> 园区概览</div>
+      <div className="bd-strip-chips">
+        {chips.map((c, i) => (
+          <div className="bd-chip" key={i}>
+            <span className="bd-chip-ico"><Icon name={c.icon} size={15} /></span>
+            <span className="bd-chip-label">{c.label}</span>
+            <b>{c.value}</b>
+          </div>
+        ))}
+      </div>
+    </footer>
+  );
+}

src/components/ScreenLayout.jsx

@@ -0,0 +1,23 @@
+import { Outlet } from 'react-router-dom';
+import PageHeader from './PageHeader';
+import { usePageNav } from '../utils/pageNav';
+
+/* =========================================================
+   ScreenLayout —— 大屏页面统一布局
+   通过 App 嵌套路由注入统一页眉 + 全局左右键循环导航
+   页脚由各页面按需自行渲染（数字孪生页无需页脚）
+   ========================================================= */
+
+export default function ScreenLayout() {
+  // 全局左右方向键循环切换（数据大屏 / 数字孪生 / 媒体轮播）
+  usePageNav();
+
+  return (
+    <div className="bd-layout">
+      <PageHeader />
+      <main className="bd-layout-main">
+        <Outlet />
+      </main>
+    </div>
+  );
+}