Add first version for crossfade plugin

plugins/crossfade/back.js

@@ -0,0 +1,13 @@
+const { ipcMain } = require("electron");
+const { Innertube } = require("youtubei.js");
+
+module.exports = async (win, options) => {
+	const yt = await Innertube.create();
+
+	ipcMain.handle("audio-url", async (_, videoID) => {
+		const info = await yt.getBasicInfo(videoID);
+		const url = info.streaming_data?.formats[0].decipher(yt.session.player);
+
+		return url;
+	});
+};