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

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

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>