perf: reduce CPU usage and unify next-track buffering settings

- Throttle audio:progress from 100ms to 500ms; WaveformSeek and
  FsSeekbar use imperative DOM updates instead of React re-renders
- Fix all usePlayerStore() calls without selectors across pages and
  components (useShallow / individual selectors throughout)
- Remove filter:blur and transform:scale from Hero, AlbumDetail and
  FullscreenPlayer backgrounds — eliminated expensive software
  compositing layers on WebKitGTK
- Replace translate3d with 2D translate in FS mesh and portrait
  animations; remove will-change:transform from mesh blobs
- Move Hot Cache section from Storage tab to Audio tab; group Preload
  and Hot Cache under a shared 'Next Track Buffering' section with a
  mutual-exclusivity note and auto-disable logic
- Add 'off' toggle to Preload (replaces Off button with toggle switch);
  enabling either method now automatically disables the other

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/components/SongInfoModal.tsx

@@ -2,6 +2,7 @@ import React, { useEffect, useState } from 'react';
 import { createPortal } from 'react-dom';
 import { X } from 'lucide-react';
 import { usePlayerStore } from '../store/playerStore';
+import { useShallow } from 'zustand/react/shallow';
 import { getSong, SubsonicSong } from '../api/subsonic';
 import { useTranslation } from 'react-i18next';
 
@@ -33,7 +34,9 @@ function Divider() {
 
 export default function SongInfoModal() {
   const { t } = useTranslation();
-  const { songInfoModal, closeSongInfo } = usePlayerStore();
+  const { songInfoModal, closeSongInfo } = usePlayerStore(
+    useShallow(s => ({ songInfoModal: s.songInfoModal, closeSongInfo: s.closeSongInfo }))
+  );
   const [song, setSong] = useState<SubsonicSong | null>(null);
   const [loading, setLoading] = useState(false);