The finance team wants to understand the size of its highest-value paid orders.
From orders, find the three largest individual orders with status = 'paid' and report the average of their amount_usd values, rounded to two decimal places.
The three orders must be chosen from paid orders only. A delivered, refunded, cancelled, or otherwise non-paid order cannot take one of the three positions, even if its amount is high.
Ordering: Return a single row; sorting the final result is not required.