fix: preload=auto, artwork pre-warm, AbortError reload (matching Kima Hub)

- Add preload="auto" playsinline to <audio> element: browser starts
  buffering as soon as src is set, not only when play() is called —
  critical for background where play() has no data to work with
- Fix AbortError handling: instead of silently returning (was swallowing
  audio element bad-state errors), reload src + load() like Kima Hub
  so the already-registered canplay listener retries play() once buffered
- Pre-warm next song's cover art in _preloadNext() using _cachedCoverUrl
  so the lock screen notification never cold-starts artwork on first skip
- Move _coverCache to top of file so _preloadNext and updateMediaSession
  share the same stable token URLs

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

src/player.js

@@ -5,6 +5,17 @@ import { api, streamUrl, coverUrl, downloadUrl } from './api.js';
 import { loadRecommendations } from './views.js';
 import { updateLyricsHighlight, onNpSongChange } from './nowplaying.js';
 
+// ─── COVER ART URL CACHE ───
+// Stable URLs let the OS cache artwork images — without this every skip regenerates a new
+// auth token URL, Samsung has to re-fetch the image, and the lock screen notification
+// visually reloads. Defined here (top of file) so both preload and MediaSession can use it.
+const _coverCache = new Map();
+function _cachedCoverUrl(id, size) {
+  const key = `${id}:${size}`;
+  if (!_coverCache.has(key)) _coverCache.set(key, coverUrl(id, size));
+  return _coverCache.get(key);
+}
+
 // ─── PRELOAD (resource hint keeps connection open through Doze gap) ───
 let _preUrl  = '';
 let _preId   = '';
@@ -31,6 +42,14 @@ function _preloadNext() {
   _preLink.as   = 'fetch';
   _preLink.href = _preUrl;
   document.head.appendChild(_preLink);
+  // Pre-warm cover art so lock screen notification never cold-starts artwork on first skip.
+  // Uses _cachedCoverUrl so the same token is reused when updateMediaSession() runs later.
+  if(next.coverArt) {
+    [96, 300, 512].forEach(size => {
+      const img = new Image();
+      img.src = _cachedCoverUrl(next.coverArt, size);
+    });
+  }
 }
 
 function _clearPreload() {
@@ -73,8 +92,15 @@ export function playCurrent() {
     try { if(navigator.audioSession) navigator.audioSession.type = 'playback'; } catch {}
     S.audio.play().catch(err => {
       S._trackChanging = false;
-      if (err?.name === 'AbortError') return; // src changed mid-flight, stop
-      if (attempt < 4 && S.queue[S.qIdx]?.id === s.id) {
+      if (S.queue[S.qIdx]?.id !== s.id) return; // song changed while we waited — stop
+      if (err?.name === 'AbortError') {
+        // Audio element in bad state (interruption or load race) — reload like Kima Hub does
+        S._trackChanging = true;
+        S.audio.src = src;
+        S.audio.load(); // canplay listener above will call play() once buffered
+        return;
+      }
+      if (attempt < 4) {
         setTimeout(() => {
           if (S.queue[S.qIdx]?.id !== s.id) return;
           S._trackChanging = true;
@@ -354,16 +380,6 @@ export function setVolume(v) {
 }
 
 // ─── MEDIA SESSION ───
-// Cache cover art URLs — same auth token is reused so the OS can cache the artwork image.
-// Without this, every metadata update regenerates a new token URL and Samsung re-fetches
-// the artwork on each skip, causing the notification to visually "restart".
-const _coverCache = new Map();
-function _cachedCoverUrl(id, size) {
-  const key = `${id}:${size}`;
-  if (!_coverCache.has(key)) _coverCache.set(key, coverUrl(id, size));
-  return _coverCache.get(key);
-}
-
 export function updateMediaSession(s) {
   // Android native MediaSession bridge — use 512px art for high-DPI screens
   if (window.Android) {