feat: add SFX volume control and improve audio feedback

- Implemented separate sound effects volume control in settings.
- Updated backend to handle new `sfx_volume` parameter.
- Enhanced UI to include sound effects volume slider in admin panel.
- Integrated sound effects for various user interactions (clicks, navigation, alerts).
- Added a new global sound engine to manage audio synthesis without external files.
- Updated documentation for Docker deployment and Windows packaging.
- Refactored audio context management to ensure sound effects are available post user interaction.

src/utils/pageNav.js

@@ -1,5 +1,6 @@
 import { useEffect } from 'react';
 import { useNavigate, useLocation } from 'react-router-dom';
+import { Sfx } from './sounds';
 
 /* =========================================================
    页面循环导航 —— 左右方向键切换大屏页面
@@ -34,8 +35,10 @@ export function usePageNav() {
       if (idx === -1) return;
       const n = PAGE_ORDER.length;
       if (e.key === 'ArrowRight') {
+        Sfx.page();
         navigate(PAGE_ORDER[(idx + 1) % n].path);
       } else if (e.key === 'ArrowLeft') {
+        Sfx.page();
         navigate(PAGE_ORDER[(idx - 1 + n) % n].path);
       }
     };