feat(queue): switchable queue display mode (Queue vs Playlist) (#922)

* feat(queue): add queueDisplayMode setting with rehydrate (default queue)

* feat(queue): render upcoming-only or full timeline by mode, with header toggle

* feat(settings): add queue display mode toggle to Personalisation

* i18n: queue display mode strings across all locales

* test(queue): display-mode rendering and absolute index mapping

* docs: changelog + credits for queue display mode (#922)

src/locales/en/settings.ts

@@ -391,6 +391,9 @@ export const settings = {
   integrationsPrivacyTitle: 'Privacy notice',
   integrationsPrivacyBody: 'All integrations on this tab are <strong>opt-in</strong> and send data to external services or to your Navidrome server when enabled. Last.fm receives your listening history, Discord shows the currently playing track in your profile, Bandsintown is queried per artist to fetch tour dates, and the Now-Playing share publishes your current track to other users of your Navidrome server. If you don\'t want any of this, simply leave the corresponding section disabled.',
   homeCustomizerTitle: 'Home Page',
+  queueModeTitle: 'Queue Display Mode',
+  queueModeQueueSub: 'Show only upcoming tracks. The current track stays in the header and leaves the list once it has played.',
+  queueModePlaylistSub: 'Keep the whole queue in the list with the current track highlighted at the top; played tracks stay.',
   queueToolbarTitle: 'Queue Toolbar',
   queueToolbarReset: 'Reset to default',
   queueToolbarSeparator: 'Separator',