add global music folder selector

src/renderer/api/utils-music-folder.ts

@@ -0,0 +1,24 @@
+import { ServerListItemWithCredential } from '/@/shared/types/domain-types';
+
+export const mergeMusicFolderId = <T extends { musicFolderId?: string | string[] }>(
+    query: T,
+    server: null | ServerListItemWithCredential,
+): T => {
+    if (
+        !server ||
+        !server.musicFolderId ||
+        server.musicFolderId.length === 0 ||
+        query.musicFolderId
+    ) {
+        return query;
+    }
+
+    // Only merge if server matches and musicFolderId is not already in query
+    const musicFolderId =
+        server.musicFolderId.length === 1 ? server.musicFolderId[0] : server.musicFolderId;
+
+    return {
+        ...query,
+        musicFolderId,
+    };
+};