feat(orbit): show track attribution in host queue + host label in guest queue

Before: the guest queue already labelled guest-suggested tracks with
"Suggested by {user}", but host picks had no label — and the host's own
queue had no attribution at all. The host couldn't tell which upcoming
rows came from guests without checking the pending-approvals list.

- Guest queue: host-pick rows now show "Added by host" instead of hiding
  the attribution line.
- Host queue: each row (and the current track) shows "Added by you" or
  "Added by {user}" while an Orbit session is active. Lookup uses the
  existing OrbitState.queue / currentTrack addedBy field, so no new
  protocol fields.

New i18n keys (en+de+fr+nl+zh+nb+ru+es):
  orbit.queueAddedByHost · queueAddedByYou · queueAddedByUser

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/locales/en.ts

@@ -1654,6 +1654,9 @@ export const enTranslation = {
     approvalDecline: 'Decline',
     guestUpNextMore: '+ {{count}} more in the host\'s queue',
     guestSubmitter: 'by {{user}}',
+    queueAddedByHost: 'Added by host',
+    queueAddedByYou: 'Added by you',
+    queueAddedByUser: 'Added by {{user}}',
     guestEmpty: 'No suggestions yet. Open a track\'s context menu and pick "Add to Orbit session".',
     guestFooter: "The host controls playback — you can't change the list.",
     exitKickedTitle: 'You were banned from the session',