radio: refactor LRC fetching to directly use asyncio for backgrounding, and add null check for album art in RadioUtil

endpoints/radio.py

@@ -434,7 +434,7 @@ class Radio(FastAPI):
         next["end"] = time_ends
 
         # Use BackgroundTasks for LRC fetch/cache
-        background_tasks.add_task(self._do_lrc_fetch, data.station, next.copy())
+        asyncio.create_task(self._do_lrc_fetch(data.station, next.copy()))
 
         try:
             background_tasks.add_task(self.radio_util.webhook_song_change, next, data.station)