feat(library): play all and shuffle all on every track list

Four pages that list tracks — Tracks, genre, artist, and both playlist
views — had no way to start the whole list, or had a broken one. One
shared helper (utils/play-all.ts) now owns what "shuffle this
collection" means: SetQueue's shuffleStart only picks a random first
track when shuffle mode is already on, it does not turn it on, so the
mode is toggled before the queue is set. Each host passes an honest
queue Source (#14): anything that builds a queue names what it built it
from, so "Playing from" stops lying.

Two behaviour changes ride along, both flagged: smart-playlist-details'
Shuffle was a live no-op (shuffleStart without enabling mode played
track 1 in order) and is fixed; playlist-details' Play all drops its
shuffleStart:true, so with shuffle mode already on it now starts at the
first row instead of a random one — the album page's existing
semantics.

Verified: make ui-test (1147, incl. a case that fails when the
smart-playlist fix is reverted), npx tsc --noEmit, make e2e (255,
incl. new play-all and header-fit specs), make lint, make test,
make bindings-check, make css-check; artist header read from
screenshots at 424/320/900 (the pair wraps below the name on a phone).

Closes #31

frontend/src/components/explore-album-details/explore-album-details.ts

@@ -43,6 +43,7 @@ import type * as autotagservice from '@go/autotagservice/models.js';
 import { confirmAction } from '../confirm-dialog/confirm-dialog';
 import { queueStore } from '../../store/queue-store';
 import type { QueueSource } from '../../store/queue-store';
+import { playAll } from '@utils/play-all';
 import { notificationStore } from '../../store/notification-store';
 import '../notifications/inline-notice';
 import {
@@ -2771,20 +2772,11 @@ export class ExploreAlbumDetails extends LitElement implements ContextMenuHost {
 
     /** Play what the user owns of this release, optionally shuffled. */
     private playOwned(shuffle: boolean): void {
-        const paths = this.ownedFilePaths();
-
         // The button is only rendered when there is something to play,
-        // so an empty set here is not a state the user can reach.
-        if (paths.length === 0) return;
-
-        // `shuffleStart` only picks a random first track when shuffle
-        // mode is *already* on — it does not turn it on — so the mode
-        // has to be set before the queue, not after.
-        if (shuffle && !queueStore.getState().shuffleMode) {
-            queueStore.toggleShuffle();
-        }
-
-        queueStore.setQueue(paths, 0, shuffle, this.queueSource());
+        // so an empty set here is not a state the user can reach.  The
+        // shuffle-mode semantics live in `playAll`, shared with the
+        // play-all/shuffle-all pair on every track list.
+        playAll(this.ownedFilePaths(), this.queueSource(), shuffle);
     }
 
     /** Append what the user owns of this release to the queue. */