User orders and positions

Authenticated. Sends updates on a user’s open orders and current positions, including all subsequent updates. This is the only channel that accepts -USDC product IDs.

One connection per user. product_ids is optional; omit it for all products. To add products, unsubscribe and open a new connection with the expanded list.

Open orders arrive in the snapshot batched by 50. The first message with fewer than 50 orders is the last of that snapshot.