ui: add placeholder artwork

src/lib/components/player/PlayerRoot.svelte

@@ -1,5 +1,6 @@
 <script lang="ts">
 	import { onMount, setContext } from "svelte";
+	import artwork from "$lib/assets/artwork.jpg";
 	import { player } from "$lib/player/store.svelte";
 	import { songTypeNumberLabel } from "$lib/utils/amq";
 	import { AudioContext } from "./ctx.svelte";
@@ -44,6 +45,7 @@
 					title: `${track.animeName} (${typeLabel}) — ${track.title}`,
 					artist: track.artist,
 					album: track.animeName ?? "",
+					artwork: [{ src: artwork }],
 				});
 			} else {
 				navigator.mediaSession.metadata = null;