优化：公屏叫号默认播放并移除声音控制

需求：服务端下发音频已验证可用，公屏无需再显示开启声音按钮和状态提示。

实现：移除声音控制组件与首次点击门槛，新叫号到达后直接播放内置音频队列。

验证：前端 65 项测试通过，生产构建通过。

web/src/pages/PublicDisplayCenterPage.tsx

@@ -1,6 +1,5 @@
 import { useEffect, useRef } from "react";
 import { api } from "../api";
-import { AudioControl } from "../components/AudioControl";
 import { FeedbackBanner, FreshnessBanner, LoadingState } from "../components/Feedback";
 import { useAudioAnnouncements } from "../hooks/useAudioAnnouncements";
 import { usePollingResource } from "../hooks/usePollingResource";
@@ -13,7 +12,7 @@ function projectCurrentBatch(value: unknown): CallBatchDto | null {
 }
 
 export function PublicDisplayCenterPage() {
-  const { announce, audioRef, enable: enableAudio, status: audioStatus } = useAudioAnnouncements();
+  const { announce, audioRef } = useAudioAnnouncements();
   const resource = usePollingResource((signal) => api.displayOverview(signal), { intervalMs: 5_000 });
   const data = resource.data;
   const stale = Boolean(data) && isTimestampStale(resource.lastClientSuccessAt, 30_000);
@@ -38,7 +37,7 @@ export function PublicDisplayCenterPage() {
   return (
     <div className="app-shell app-shell--admin app-shell--no-primary-action">
       <a className="skip-link" href="#main-content">跳到主要内容</a>
-      <AudioControl audioRef={audioRef} status={audioStatus} onEnable={enableAudio} />
+      <audio ref={audioRef} preload="auto" aria-hidden="true" />
       <header className="app-header">
         <div className="brand-lockup" aria-label="景区排队叫号系统">
           <span className="brand-logo-frame" aria-hidden="true"><img className="brand-logo" src="/xiaoqikong-logo.jpg" alt="" /></span>