refactor(music-lab): 컴포넌트 분할 — AudioPlayer, LyricsTab, CreditsBadge 추출

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

src/pages/music/components/CreditsBadge.jsx

@@ -0,0 +1,36 @@
+import React, { useEffect, useState, useCallback } from 'react';
+import { getMusicCredits } from '../../../api';
+
+const CreditsBadge = () => {
+    const [credits, setCredits] = useState(null);
+
+    const fetchCredits = useCallback(async () => {
+        try {
+            const data = await getMusicCredits();
+            setCredits(data);
+        } catch {}
+    }, []);
+
+    useEffect(() => {
+        fetchCredits();
+        const interval = setInterval(fetchCredits, 30000);
+        return () => clearInterval(interval);
+    }, [fetchCredits]);
+
+    if (!credits) return null;
+
+    const remaining = credits.credits_left ?? credits.remaining ?? credits.data ?? null;
+    if (remaining == null) return null;
+
+    const isLow = remaining <= 10;
+
+    return (
+        <div className={`ms-credits-badge ${isLow ? 'is-low' : ''}`}>
+            <span className="ms-credits-badge__icon">⚡</span>
+            <span className="ms-credits-badge__value">{remaining}</span>
+            <span className="ms-credits-badge__label">credits</span>
+        </div>
+    );
+};
+
+export default CreditsBadge;