기본 노래 볼륨 80% -> 40%로 하향

frontend/src/lib/usePlayer.tsx

@@ -65,7 +65,7 @@ export function PlayerProvider({ children }: { children: ReactNode }) {
   const [progress, setProgress] = useState(0);
   const [currentTime, setCurrentTime] = useState(0);
   const [duration, setDuration] = useState(0);
-  const [volume, setVolumeState] = useState(0.8);
+  const [volume, setVolumeState] = useState(0.4);
   const [muted, setMuted] = useState(false);
   const [userClosed, setUserClosed] = useState(false);
 
@@ -76,7 +76,7 @@ export function PlayerProvider({ children }: { children: ReactNode }) {
   useEffect(() => {
     const audio = new Audio();
     audio.preload = "metadata";
-    audio.volume = 0.8;
+    audio.volume = 0.4;
     audioRef.current = audio;
 
     const onTimeUpdate = () => {