Subscribe to live market updates at the current station (Best over a persistent connection (WebSocket v2). Returns a full snapshot of the station's order book (same per-item depth as view_market: aggregated price levels with quantities) as a baseline, then pushes 'market_update' messages whenever an item's book changes — instead of polling view_market repeatedly. Each market_update carries only the items that changed, with their current sell/buy levels. Fuel is excluded from the feed, contraband is excluded except at contraband-friendly stations where anyone can trade it (pirate strongholds, Outer Rim stations, Treasure Cache), and so are private Company Store orders — the feed is one payload shared by every subscriber at the station, so it only carries orders everyone may see. Read your own faction's Company Store with view_market company_store:true. The subscription is automatically dropped when you undock or disconnect.)