feat(web): shared collection header, Play and Shuffle, and the centred page column (M494)

- CollectionHeader holds cover, title, facts, then Play and Shuffle, for
  album and playlist. The playlist page gains Play and Shuffle; it had
  neither. The cover uses the shared Cover component, so the playlist
  header also gets the fallback image.
- PlayActions is the one Play and Shuffle pair: filled Play, outlined
  Shuffle, on album, playlist and artist pages (operator, 2026-10-08).
  The artist page's round icon button said Play but shuffled; Play now
  keeps the server's order, and Shuffle shuffles.
- PageColumn is the playlist page's centred column, now used by album,
  playlist, Liked, History and Search → Tracks.
- The playlist page builds its queue with playlistTrackToRef, the shared
  converter, in place of its own copy. Its copy skipped only removed
  tracks, so a missing file (#2527) could still be queued from there.
- shuffled() in lib/utils is the one shuffle, replacing three private
  copies (album page, artist page, ArtistCard).
- The album's refetch error now uses text-error-fg. `text-oxblood` is
  not a colour in the theme, so it never rendered.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

web/src/routes/library/history/+page.svelte

@@ -1,4 +1,5 @@
 <script lang="ts">
+  import PageColumn from '#lib/components/PageColumn.svelte';
   import { pageTitle } from '#lib/branding.js';
   import { createHistoryQuery } from '#lib/api/history.js';
   import { groupByDay } from '#lib/utils/dayGroup.js';
@@ -29,7 +30,7 @@
 
 <svelte:head><title>{pageTitle('Library · History')}</title></svelte:head>
 
-<div class="space-y-4">
+<PageColumn>
   <header class="flex flex-wrap items-end justify-between gap-3">
     <h1 class="font-display text-2xl font-medium text-text-primary">History</h1>
     {#if flatEvents.length > 0}
@@ -83,4 +84,4 @@
       <p class="py-2 text-center text-sm text-text-secondary">End of history</p>
     {/if}
   {/if}
-</div>
+</PageColumn>