feat(web): send a "now playing" scrobble at track start

Ping Navidrome with scrobble?submission=false when a track starts so
getNowPlaying reflects it instantly (feeds e.g. a Discord rich-presence
plugin / other clients' Now Playing). Independent of the existing delayed
"played" scrobble used for play counts and Last.fm.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/player/player.js

@@ -47,6 +47,12 @@ function _cancelScrobble() {
 function _scrobbleNow(s) {
   if (s) api('scrobble', `&id=${s.id}&time=${Date.now()}`).catch(() => {});
 }
+// "Now Playing" ping (submission=false) — tells the server what's playing *right now* so
+// getNowPlaying (and e.g. a Discord rich-presence plugin) updates instantly. This is distinct
+// from the delayed "played" scrobble above, which counts the play for stats / Last.fm.
+function _scrobbleNowPlaying(s) {
+  if (s) api('scrobble', `&id=${s.id}&submission=false`).catch(() => {});
+}
 
 // Unified duration / position / seek helpers — use native state when available,
 // fall back to HTMLAudioElement when not.
@@ -404,6 +410,7 @@ export function playCurrent() {
   updateMediaSession(s);
   onNpSongChange(s.id);
   renderQueue();
+  _scrobbleNowPlaying(s);                 // "läuft gerade" sofort an Navidrome (getNowPlaying)
   _scheduleScrobble(s.id, s.duration);
 
   const _resetFlag = () => { if (_playGen === gen) S._trackChanging = false; };