Break down purchase receipts by cost/commission, harden XML validation and state I/O

Adds a full pre-load validation pass for GM XML seeds (ids, names,
options, commission, LMSR liquidity), replaces IO.print with
System.out, and surfaces detailed error messages across load/save
commands instead of generic failures.

1 files changed, 6 insertions, 1 deletions

diff --git a/api/src/main/java/market/guess/api/PurchaseReceiptDTO.java b/api/src/main/java/market/guess/api/PurchaseReceiptDTO.java
index e98a080..02e8007 100644
--- a/api/src/main/java/market/guess/api/PurchaseReceiptDTO.java
+++ b/api/src/main/java/market/guess/api/PurchaseReceiptDTO.java
@@ -2,4 +2,9 @@ package market.guess.api;
 
 import java.util.List;
 
-public record PurchaseReceiptDTO(List<TradeRowDTO> trades, MarketStateDTO stateAfter) {}
+public record PurchaseReceiptDTO(
+    List<TradeRowDTO> trades,
+    String sharesCost,
+    String commissionPaid,
+    String totalPaid,
+    MarketStateDTO stateAfter) {}