feat(web): add AlbumCard component

Grid card used on the artist detail page. Cover image, title, year.
Broken covers swap to FALLBACK_COVER via onerror.

web/src/lib/components/AlbumCard.svelte

@@ -0,0 +1,27 @@
+<script lang="ts">
+  import type { AlbumRef } from '$lib/api/types';
+  import { FALLBACK_COVER } from '$lib/media/covers';
+
+  let { album }: { album: AlbumRef } = $props();
+
+  function onImgError(e: Event) {
+    (e.currentTarget as HTMLImageElement).src = FALLBACK_COVER;
+  }
+</script>
+
+<a
+  href={`/albums/${album.id}`}
+  class="group block rounded focus-visible:ring-2 focus-visible:ring-accent"
+>
+  <img
+    src={album.cover_url}
+    alt=""
+    class="aspect-square w-full rounded object-cover transition-transform group-hover:scale-[1.03]"
+    loading="lazy"
+    onerror={onImgError}
+  />
+  <div class="mt-2 truncate text-sm font-medium">{album.title}</div>
+  {#if album.year}
+    <div class="text-xs text-text-secondary">{album.year}</div>
+  {/if}
+</a>