Added GET /fapi/v3/builder/userCommissions (USER_DATA, weight 5): paginated builder fees earned on trades of users under the caller's builder code.
Parameters: userAddresses (up to 50, comma-separated), startTime, endTime, page (default 1), limit (default 50; max 1000), nonce, signer, signature.
Covers the same trades as GET /fapi/v3/builder/userTrades, but returns only fee fields (tradeId, insertTime, orderId, symbol, feeAsset, marginAsset, builderFee, userAddress).
Users' privacy mode does not apply — trades of users with privacy mode enabled are also returned.
Time window: defaults to the past 7 days; startTime cannot be earlier than 90 days ago.