Dashboard & artist page UI refresh

The dashboard now centres on your watchlist with artist photos, chart ranks at a glance, and a recent activity feed (live updates on Pro).

Artist pages have a refreshed header with social follower counts, plus tabs for Charts, Streams, Stats, Playlists, and Sales. Stats holds release and #1 history; Streams, Playlists, and Sales are placeholders while we wire more data.

Layouts, copy, and which features sit in each tab are still being tuned — expect tweaks over the next few releases.