Add likes, follows and playlist visibility; redesign web-player UI

Backend:
- New Likes feature (toggle/get liked tracks) and endpoints
- User follow/unfollow, listening stats, public user profile
- Playlist visibility (public/private) support
- Various auth and DTO/response adjustments to support the above

Frontend (web-player):
- New design system pass: theme tokens/mode (light/dark), glass menu,
  tabs bar, player dock/extras/queue components, mix tiles, artist link
- New routes: Liked, public user profile (/u/[id]), likes API proxy
- Search refactor: shared SearchBox component used by TopBar and
  MobileHeader (search now reachable on mobile), live results as you
  type instead of requiring Enter, dropped the "Buscando…" quick-result
  preview
- Removed now-unused components (MobileNav, CoverBadge, MixBentoTile,
  PlayPauseOverlay, SuggestionsTable, userDirectory)
- Design handoff reference docs added under web-player/design_handoff_musify_player
  and web-player/docs/design-system-refactor-plan.md

web-player/src/routes/(app)/albums/+page.svelte

@@ -35,7 +35,7 @@
 	</PageHeader>
 
 	{#if items.length > 0}
-		<MediaGrid class="mt-9">
+		<MediaGrid class="mt-7 sm:mt-8">
 			{#each items as album, i (album.id)}
 				<AlbumCard
 					id={album.id}
@@ -55,10 +55,7 @@
 			description="Crea el primero y añádele las canciones que hayas subido."
 		>
 			{#snippet actions()}
-				<Button onclick={() => (creating = true)}>
-					<Plus class="h-4 w-4" strokeWidth={2} />
-					Crear álbum
-				</Button>
+				<Button onclick={() => (creating = true)}>Crear álbum</Button>
 			{/snippet}
 		</EmptyState>
 	{/if}

web-player/src/routes/(app)/albums/[id]/+page.server.ts

@@ -42,7 +42,7 @@ export const load: PageServerLoad = async ({ params, locals, url, fetch, parent
 		(track) => track.source === 'Local' && !inAlbum.has(track.id)
 	);
 
-	const isOwner = user !== null && Number(album.ownerUserId) === Number(user.sub);
+	const isOwner = user !== null && String(album.ownerUserId) === user.sub;
 
 	return { album, tracks, library, isOwner, section: isOwner ? '/albums' : null };
 };

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

@@ -48,17 +48,17 @@
 	label={isOwner ? 'Volver a tus álbumes' : 'Volver al inicio'}
 />
 
-<div class="mt-5 flex flex-col gap-5 sm:mt-6 sm:flex-row sm:items-end sm:gap-6">
+<div class="mt-3 flex flex-col gap-5 sm:mt-4 sm:flex-row sm:items-end sm:gap-6">
 	<PlaylistArt
 		{trackIds}
 		{coverUrl}
 		size="large"
-		class="h-36 w-36 shrink-0 rounded-art-lg shadow-art-lg sm:h-44 sm:w-44"
+		class="h-36 w-36 shrink-0 rounded-[18px] shadow-[0_24px_56px_rgba(0,0,0,.55)] sm:h-41 sm:w-41"
 	/>
 	<div class="min-w-0 flex-1">
-		<p class="text-sm tracking-[0.14em] text-fg-3 uppercase">Álbum</p>
+		<p class="text-[10.5px] font-semibold tracking-[0.16em] text-fg-2 uppercase">Álbum</p>
 		<h1
-			class="mt-1.5 font-display text-3xl font-semibold tracking-tight break-words text-fg sm:text-5xl md:text-7xl"
+			class="mt-1.5 font-display text-[28px] font-semibold tracking-[-0.035em] break-words text-fg sm:text-[33px]"
 		>
 			{title}
 		</h1>
@@ -72,10 +72,10 @@
 <div class="mt-6 flex flex-wrap items-center gap-2.5 sm:mt-7">
 	<Button size="sm" onclick={onPlayAll} disabled={trackIds.length === 0}>
 		{#if playing}
-			<Pause class="h-4 w-4" fill="currentColor" strokeWidth={1.5} />
+			<Pause class="h-4 w-4" strokeWidth={1.5} />
 			Pausar
 		{:else}
-			<Play class="h-4 w-4" fill="currentColor" strokeWidth={1.5} />
+			<Play class="h-4 w-4" strokeWidth={1.5} />
 			Reproducir
 		{/if}
 	</Button>

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

@@ -31,18 +31,16 @@
 
 <TrackTable index action={isOwner} class="mt-6 sm:mt-8">
 	{#each tracks as track, i (track.id)}
-		<TrackRow>
-			<TrackIndexCell
-				index={i}
-				active={player.current.id === queueIdForTrack(track)}
-				playing={player.playing}
-				onToggle={() => playFrom(i)}
-			/>
+		{@const active = player.current.id === queueIdForTrack(track)}
+		<TrackRow {active}>
+			<TrackIndexCell index={i} {active} playing={player.playing} onToggle={() => playFrom(i)} />
 			<TrackTitleCell
 				trackId={track.id}
 				title={track.title}
 				artist={track.artist}
+				ownerUserId={track.ownerUserId}
 				explicit={track.isExplicit}
+				{active}
 				onClick={() => playFrom(i)}
 			/>
 			<TrackMeta>{fmtTime(Number(track.duration))}</TrackMeta>

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

@@ -28,12 +28,15 @@
 	<SectionHeading title="Tus canciones subidas" />
 	<TrackTable action>
 		{#each library as track, i (track.id)}
-			<TrackRow>
+			{@const active = player.current.id === track.id}
+			<TrackRow {active}>
 				<TrackTitleCell
 					trackId={track.id}
 					title={track.title}
 					artist={track.artist}
+					ownerUserId={track.ownerUserId}
 					explicit={track.isExplicit}
+					{active}
 					onClick={() => playFrom(i)}
 				>
 					{#snippet overlay()}

web-player/src/routes/(app)/albums/external/[source]/[externalId]/+page.svelte

@@ -79,21 +79,21 @@
 <Page>
 	<BackLink href="/explore" label="Volver a explorar" />
 
-	<div class="mt-5 flex flex-col gap-5 sm:mt-6 sm:flex-row sm:items-end sm:gap-6">
+	<div class="mt-3 flex flex-col gap-5 sm:mt-4 sm:flex-row sm:items-end sm:gap-6">
 		<Cover
 			trackId={album.albumId}
 			src={album.thumbnailUrl}
 			size="large"
 			alt={album.title}
-			class="h-36 w-36 shrink-0 rounded-art-lg shadow-art-lg sm:h-44 sm:w-44"
+			class="h-36 w-36 shrink-0 rounded-[18px] shadow-[0_24px_56px_rgba(0,0,0,.55)] sm:h-41 sm:w-41"
 			oncontextmenu={(e) => (albumMenu = albumContextMenuStateFor(e, 'youtube', album.albumId))}
 		/>
 		<div class="min-w-0 flex-1">
-			<p class="text-sm tracking-[0.14em] text-fg-3 uppercase">
+			<p class="text-[10.5px] font-semibold tracking-[0.16em] text-fg-2 uppercase">
 				{album.isSingle ? 'Single' : album.isEp ? 'EP' : 'Álbum'}
 			</p>
 			<h1
-				class="mt-1.5 font-display text-3xl font-semibold tracking-tight break-words text-fg sm:text-5xl md:text-7xl"
+				class="mt-1.5 font-display text-[28px] font-semibold tracking-[-0.035em] break-words text-fg sm:text-[33px]"
 			>
 				{album.title}
 			</h1>
@@ -113,10 +113,10 @@
 	<div class="mt-6 flex flex-wrap items-center gap-2.5 sm:mt-7">
 		<Button size="sm" onclick={playAll} disabled={queue.length === 0}>
 			{#if isCurrentQueue && player.playing}
-				<Pause class="h-4 w-4" fill="currentColor" strokeWidth={1.5} />
+				<Pause class="h-4 w-4" strokeWidth={1.5} />
 				Pausar
 			{:else}
-				<Play class="h-4 w-4" fill="currentColor" strokeWidth={1.5} />
+				<Play class="h-4 w-4" strokeWidth={1.5} />
 				Reproducir
 			{/if}
 		</Button>
@@ -132,19 +132,19 @@
 
 	<TrackTable index class="mt-6 sm:mt-8">
 		{#each tracks as track, i (track.videoId)}
-			<TrackRow oncontextmenu={(e) => (contextMenu = contextMenuStateFor(e, targetFor(i)))}>
-				<TrackIndexCell
-					index={i}
-					active={player.current.id === track.videoId}
-					playing={player.playing}
-					onToggle={() => playFrom(i)}
-				/>
+			{@const active = player.current.id === track.videoId}
+			<TrackRow
+				{active}
+				oncontextmenu={(e) => (contextMenu = contextMenuStateFor(e, targetFor(i)))}
+			>
+				<TrackIndexCell index={i} {active} playing={player.playing} onToggle={() => playFrom(i)} />
 				<TrackTitleCell
 					trackId={track.videoId}
 					title={track.title}
 					artist={album.artist}
 					coverSrc={album.thumbnailUrl}
 					explicit={track.isExplicit}
+					{active}
 					onClick={() => playFrom(i)}
 				/>
 				<TrackMeta>{fmtTime(Number(track.durationSeconds))}</TrackMeta>