Add pause controls and app attribution to the web app

Settings gets a Sharing card (pause 1 hour / until tomorrow / until
turned back on); the feed shows a resume banner while paused. Now-playing
cards say which app a phone reported, e.g. "via Spotify".

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01MzFywujuH9TiuXbr9vjoX8

apps/web/src/components/NowPlayingCard.tsx

@@ -31,7 +31,7 @@ export function NowPlayingCard({
         <span className="row">
           <span className={`status ${np.isPlaying ? 'status-live' : ''}`}>
             {np.isPlaying ? 'Listening now' : `Played ${timeAgo(np.updatedAt)}`}
-            <span className="muted"> via {SERVICE_LABELS[np.source]}</span>
+            <span className="muted"> via {np.sourceApp ?? SERVICE_LABELS[np.source]}</span>
           </span>
           {onTogglePin && (
             <button