docs: reorder & testing

pkg/schema/fbs/order.fbs

@@ -1,4 +1,6 @@
 // order reflects model/order/Order data object
+include "common.fbs";
+
 namespace order;
 
 enum Relation : byte {
@@ -193,9 +195,31 @@ table CommandItem {
   payload: CommandPayload (required);
 }
 
-table Order {
+// UserGamesCommand is the signed-gRPC request payload for
+// `MessageTypeUserGamesCommand`. game_id selects the target running
+// game; gateway re-encodes commands into the engine JSON shape and
+// forwards through `POST /api/v1/user/games/{game_id}/commands`.
+table UserGamesCommand {
+  game_id: common.UUID (required);
+  commands: [CommandItem];
+}
+
+// UserGamesOrder is the signed-gRPC request payload for
+// `MessageTypeUserGamesOrder`. Identical to UserGamesCommand but
+// carries `updated_at` so the order-validate path can reject stale
+// submissions.
+table UserGamesOrder {
+  game_id: common.UUID (required);
   updated_at: int64;
   commands: [CommandItem];
 }
 
-root_type Order;
+// UserGamesCommandResponse is the success acknowledgement returned
+// for `MessageTypeUserGamesCommand`. The engine answers with
+// `204 No Content` on success, so the FB shape is intentionally empty
+// — kept as a typed envelope for future extension.
+table UserGamesCommandResponse {}
+
+// UserGamesOrderResponse is the success acknowledgement returned for
+// `MessageTypeUserGamesOrder`. Mirrors `UserGamesCommandResponse`.
+table UserGamesOrderResponse {}