feat(music): YouTube 탭 컴파일 서브탭 추가 (다중 트랙 FFmpeg concat)

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

src/pages/music/MusicStudio.css

@@ -3085,3 +3085,98 @@
     .yt-table__row span:nth-child(4),
     .yt-table__row span:nth-child(5) { display: none; }
 }
+
+/* ── Compile subtab ── */
+.yt-compile-tracklist {
+    display: flex;
+    flex-direction: column;
+    gap: 2px;
+    max-height: 280px;
+    overflow-y: auto;
+}
+
+.yt-compile-track {
+    display: flex;
+    align-items: center;
+    gap: 8px;
+    padding: 7px 10px;
+    border-radius: 6px;
+    cursor: pointer;
+    transition: background 0.1s;
+}
+
+.yt-compile-track:hover { background: #1f2937; }
+.yt-compile-track.is-selected { background: #0a2e18; }
+
+.yt-compile-track__check {
+    width: 16px;
+    font-size: 11px;
+    color: #22c55e;
+    flex-shrink: 0;
+}
+
+.yt-compile-track__title {
+    flex: 1;
+    font-size: 12px;
+    color: #ccc;
+    white-space: nowrap;
+    overflow: hidden;
+    text-overflow: ellipsis;
+}
+
+.yt-compile-track__dur {
+    font-size: 10px;
+    color: #6b7280;
+    flex-shrink: 0;
+}
+
+.yt-compile-order {
+    display: flex;
+    flex-direction: column;
+    gap: 4px;
+    margin-bottom: 14px;
+}
+
+.yt-compile-order__row {
+    display: flex;
+    align-items: center;
+    gap: 8px;
+    padding: 6px 8px;
+    background: #1f2937;
+    border-radius: 6px;
+}
+
+.yt-compile-order__num {
+    width: 20px;
+    font-size: 11px;
+    color: #6b7280;
+    text-align: center;
+    flex-shrink: 0;
+}
+
+.yt-compile-order__title {
+    flex: 1;
+    font-size: 12px;
+    color: #ccc;
+    white-space: nowrap;
+    overflow: hidden;
+    text-overflow: ellipsis;
+}
+
+.yt-compile-order__btns {
+    display: flex;
+    gap: 3px;
+    flex-shrink: 0;
+}
+
+.yt-compile-settings {
+    display: flex;
+    flex-direction: column;
+    gap: 10px;
+    margin-bottom: 12px;
+}
+
+.yt-compile-slider {
+    width: 100%;
+    accent-color: #22c55e;
+}