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/player/TrackInfo.svelte

@@ -0,0 +1,32 @@
+<script lang="ts">
+	import { player } from '$lib/player/player.svelte';
+	import Cover from '$lib/components/ui/Cover.svelte';
+	import ExplicitBadge from '$lib/components/ui/ExplicitBadge.svelte';
+</script>
+
+<div class="flex min-w-0 items-center gap-3">
+	{#if player.current.id}
+		<Cover
+			trackId={player.current.id}
+			src={player.current.coverUrl}
+			hue={player.current.hue}
+			size="small"
+			alt={player.current.title}
+			class="h-13 w-13 shrink-0 rounded-lg shadow-[0_6px_16px_-6px_rgba(0,0,0,0.6)]"
+		/>
+	{:else}
+		<div
+			class="h-13 w-13 shrink-0 rounded-lg shadow-[0_6px_16px_-6px_rgba(0,0,0,0.6)]"
+			style="background:{player.artGradient}"
+		></div>
+	{/if}
+	<div class="min-w-0">
+		<div class="flex min-w-0 items-center gap-1.5">
+			{#if player.current.explicit}
+				<ExplicitBadge />
+			{/if}
+			<span class="truncate text-fg">{player.current.title}</span>
+		</div>
+		<div class="truncate text-sm text-muted">{player.current.artist || '—'}</div>
+	</div>
+</div>