Checkpoint web-player design-system refactor and backend track genre tagging

Advances the ongoing token/componentization cleanup (anchored player dock,
border-based panels instead of floating shadows, corrected light-mode
accent/gradient tokens) alongside in-progress backend support for track
genre tags.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

web-player/src/routes/(app)/albums/[id]/components/AlbumHeader.svelte

@@ -55,7 +55,7 @@
 			{trackIds}
 			{coverUrl}
 			size="large"
-			class="h-36 w-36 shrink-0 rounded-[18px] shadow-cover-lg sm:h-41 sm:w-41"
+			class="h-36 w-36 shrink-0 rounded-art-lg sm:h-41 sm:w-41"
 		/>
 	{/snippet}
 	{#snippet actions()}