feat(web): full-screen NowPlaying view

Mirrors Android's NowPlayingScreen. New /now-playing route renders
outside the Shell (no top bar, no PlayerBar) so it's a focused full
viewport: large square cover, title + linked artist/album, full-width
scrubber with timestamps, prominent transport (prev / play-pause /
next, with a 56dp circular play button), shuffle + repeat toggles,
like button, volume slider, and a queue button that opens the
existing queue drawer.

Tapping the cover or title area in PlayerBar (compact + desktop)
now navigates to /now-playing instead of the album page. Pattern
matches Spotify / YouTube Music. The album link stays reachable via
the album-name link inside NowPlaying itself, so no nav is lost.

Back button in the NowPlaying header uses history.back() with a
fallback to /. Empty state when no track is loaded points the user
at Home or the Library.

Scribe 528, local task #62.

web/src/routes/+layout.svelte

@@ -151,7 +151,7 @@
 <QueueDrawer />
 
 <QueryClientProvider client={queryClient}>
-  {#if user.value !== null && page.url.pathname !== '/login'}
+  {#if user.value !== null && page.url.pathname !== '/login' && page.url.pathname !== '/now-playing'}
     <Shell>{@render children()}</Shell>
   {:else}
     {@render children()}

web/src/routes/now-playing/+page.svelte

@@ -0,0 +1,241 @@
+<script lang="ts">
+  import {
+    ArrowLeft, SkipBack, SkipForward, Play, Pause, Loader2,
+    Shuffle, Repeat, Repeat1,
+    Volume2, Volume1, VolumeX,
+    ListMusic
+  } from 'lucide-svelte';
+  import { goto } from '$app/navigation';
+  import {
+    player,
+    togglePlay, skipNext, skipPrev, seekTo, setVolume,
+    toggleShuffle, cycleRepeat,
+    toggleQueueDrawer
+  } from '$lib/player/store.svelte';
+  import { formatDuration } from '$lib/media/duration';
+  import { FALLBACK_COVER, coverUrl } from '$lib/media/covers';
+  import LikeButton from '$lib/components/LikeButton.svelte';
+  import { pageTitle } from '$lib/branding';
+
+  const current = $derived(player.current);
+
+  const skipPrevDisabled = $derived(player.index === 0 && player.position < 3);
+  const skipNextDisabled = $derived(
+    player.index === player.queue.length - 1 && player.repeat === 'off'
+  );
+
+  const repeatLabel = $derived(
+    player.repeat === 'off' ? 'Repeat off' :
+    player.repeat === 'all' ? 'Repeat all' : 'Repeat one'
+  );
+
+  const VolumeIcon = $derived(
+    player.volume === 0 ? VolumeX :
+    player.volume < 0.5 ? Volume1 : Volume2
+  );
+
+  function onSeekInput(e: Event) {
+    const v = Number((e.currentTarget as HTMLInputElement).value);
+    seekTo(v);
+  }
+  function onVolumeInput(e: Event) {
+    const v = Number((e.currentTarget as HTMLInputElement).value);
+    setVolume(v);
+  }
+  function onCoverError(e: Event) {
+    (e.currentTarget as HTMLImageElement).src = FALLBACK_COVER;
+  }
+  function goBack() {
+    // Most users land here from the PlayerBar — history.back() returns
+    // them to whatever surface they were on. If there's nothing to go
+    // back to (deep link), fall through to Home.
+    if (window.history.length > 1) {
+      window.history.back();
+    } else {
+      goto('/');
+    }
+  }
+</script>
+
+<svelte:head><title>{pageTitle(current ? `${current.title} · ${current.artist_name}` : 'Now playing')}</title></svelte:head>
+
+<div class="flex h-screen flex-col bg-background text-text-primary">
+  <header class="flex items-center px-4 py-3">
+    <button
+      type="button"
+      onclick={goBack}
+      aria-label="Back"
+      class="flex items-center justify-center min-h-[44px] min-w-[44px] rounded
+             text-text-secondary hover:text-text-primary
+             focus-visible:ring-2 focus-visible:ring-accent"
+    >
+      <ArrowLeft size={22} strokeWidth={1.5} />
+    </button>
+    <div class="ml-2 text-xs uppercase tracking-wide text-text-secondary">Now playing</div>
+  </header>
+
+  {#if !current}
+    <div class="flex flex-1 items-center justify-center px-4 text-center">
+      <p class="text-text-secondary">
+        Nothing playing yet. Pick something from
+        <a href="/" class="text-text-primary underline">Home</a>
+        or
+        <a href="/library" class="text-text-primary underline">your Library</a>.
+      </p>
+    </div>
+  {:else}
+    <main class="flex flex-1 flex-col items-center justify-center gap-6 px-4 pb-6">
+      <div class="aspect-square w-full max-w-md overflow-hidden rounded-lg bg-surface-hover shadow-lg">
+        <img
+          src={coverUrl(current.album_id)}
+          alt=""
+          class="h-full w-full object-cover"
+          onerror={onCoverError}
+        />
+      </div>
+
+      <div class="w-full max-w-md text-center">
+        <h1 class="font-display text-2xl font-medium leading-tight">
+          {current.title}
+        </h1>
+        <p class="mt-1 text-sm">
+          <a
+            href={`/artists/${current.artist_id}`}
+            class="text-text-secondary hover:text-text-primary hover:underline"
+          >
+            {current.artist_name}
+          </a>
+          {#if current.album_title}
+            <span class="text-text-secondary"> · </span>
+            <a
+              href={`/albums/${current.album_id}`}
+              class="text-text-secondary hover:text-text-primary hover:underline"
+            >
+              {current.album_title}
+            </a>
+          {/if}
+        </p>
+      </div>
+
+      <div class="w-full max-w-md">
+        <input
+          type="range"
+          min="0"
+          max={player.duration || 0}
+          step="0.1"
+          value={player.position}
+          oninput={onSeekInput}
+          aria-label="Seek"
+          class="w-full accent-accent"
+        />
+        <div class="mt-1 flex justify-between text-xs text-text-secondary tabular-nums">
+          <span>{formatDuration(player.position)}</span>
+          <span>{formatDuration(player.duration)}</span>
+        </div>
+      </div>
+
+      <div class="flex items-center gap-2">
+        <button
+          type="button"
+          onclick={toggleShuffle}
+          aria-label="Shuffle"
+          aria-pressed={player.shuffle}
+          class="flex items-center justify-center min-h-[44px] min-w-[44px] rounded
+                 {player.shuffle ? 'text-accent' : 'text-text-secondary hover:text-text-primary'}
+                 focus-visible:ring-2 focus-visible:ring-accent"
+        >
+          <Shuffle size={20} strokeWidth={1.5} />
+        </button>
+
+        <button
+          type="button"
+          onclick={skipPrev}
+          disabled={skipPrevDisabled}
+          aria-label="Previous"
+          class="flex items-center justify-center min-h-[44px] min-w-[44px] rounded
+                 text-text-primary disabled:text-text-secondary disabled:cursor-not-allowed
+                 focus-visible:ring-2 focus-visible:ring-accent"
+        >
+          <SkipBack size={26} strokeWidth={1.5} />
+        </button>
+
+        <button
+          type="button"
+          onclick={togglePlay}
+          aria-label={player.state === 'playing' ? 'Pause' : 'Play'}
+          class="flex items-center justify-center min-h-[56px] min-w-[56px] rounded-full
+                 bg-text-primary text-background
+                 focus-visible:ring-2 focus-visible:ring-accent"
+        >
+          {#if player.state === 'loading'}
+            <Loader2 size={28} strokeWidth={2} class="animate-spin" />
+          {:else if player.state === 'playing'}
+            <Pause size={28} strokeWidth={2} />
+          {:else}
+            <Play size={28} strokeWidth={2} />
+          {/if}
+        </button>
+
+        <button
+          type="button"
+          onclick={skipNext}
+          disabled={skipNextDisabled}
+          aria-label="Next"
+          class="flex items-center justify-center min-h-[44px] min-w-[44px] rounded
+                 text-text-primary disabled:text-text-secondary disabled:cursor-not-allowed
+                 focus-visible:ring-2 focus-visible:ring-accent"
+        >
+          <SkipForward size={26} strokeWidth={1.5} />
+        </button>
+
+        <button
+          type="button"
+          onclick={cycleRepeat}
+          aria-label={repeatLabel}
+          aria-pressed={player.repeat !== 'off'}
+          class="flex items-center justify-center min-h-[44px] min-w-[44px] rounded
+                 {player.repeat !== 'off' ? 'text-accent' : 'text-text-secondary hover:text-text-primary'}
+                 focus-visible:ring-2 focus-visible:ring-accent"
+        >
+          {#if player.repeat === 'one'}
+            <Repeat1 size={20} strokeWidth={1.5} />
+          {:else}
+            <Repeat size={20} strokeWidth={1.5} />
+          {/if}
+        </button>
+      </div>
+
+      <div class="flex w-full max-w-md items-center justify-between gap-4">
+        <div class="flex items-center gap-2">
+          <LikeButton entityType="track" entityId={current.id} />
+        </div>
+
+        <div class="flex flex-1 items-center gap-2 px-4">
+          <VolumeIcon size={18} strokeWidth={1.5} class="text-text-secondary" />
+          <input
+            type="range"
+            min="0"
+            max="1"
+            step="0.01"
+            value={player.volume}
+            oninput={onVolumeInput}
+            aria-label="Volume"
+            class="flex-1 accent-accent"
+          />
+        </div>
+
+        <button
+          type="button"
+          onclick={toggleQueueDrawer}
+          aria-label="Open queue"
+          class="flex items-center gap-1.5 rounded px-3 py-2 min-h-[44px]
+                 text-text-secondary hover:text-text-primary
+                 focus-visible:ring-2 focus-visible:ring-accent"
+        >
+          <ListMusic size={20} strokeWidth={1.5} />
+          <span class="text-sm tabular-nums">{player.queue.length}</span>
+        </button>
+      </div>
+    </main>
+  {/if}
+</div>