refactor: rename frontend/ to web-player/ and format with prettier

Updates the compose build context, the Dockerfile header, the package
name and the docs. The compose service and container keep the name
frontend/musify-frontend, since nginx routes to http://frontend:3000.

The source files also carry the first prettier pass, so the rename and
the reformat land together for them.

web-player/src/lib/components/ui/TrackRow.svelte

@@ -0,0 +1,24 @@
+<script lang="ts">
+	import { getContext } from 'svelte';
+	import type { Snippet } from 'svelte';
+	import { trackTableKey, type TrackTableContext } from './TrackTable.svelte';
+
+	interface Props {
+		class?: string;
+		oncontextmenu?: (event: MouseEvent) => void;
+		children: Snippet;
+	}
+
+	let { class: klass = '', oncontextmenu, children }: Props = $props();
+
+	const table = getContext<TrackTableContext>(trackTableKey);
+</script>
+
+<!-- svelte-ignore a11y_no_static_element_interactions -->
+<div
+	class="group grid items-center gap-8 rounded-control px-3 py-2.5 transition hover:bg-surface {klass}"
+	style="grid-template-columns:{table.columns}"
+	{oncontextmenu}
+>
+	{@render children()}
+</div>