fixes

proto/cart.proto

@@ -34,6 +34,13 @@ message AddItem {
   optional uint32 parentId = 23;
   string cgm = 25;
   optional google.protobuf.Timestamp reservationEndTime = 26;
+  // extra_json carries arbitrary product data (the flat product document minus
+  // the fields mapped above) as raw JSON. It is stored losslessly and surfaced
+  // as flattened keys on the cart item.
+  bytes extra_json = 27;
+  // custom_fields holds optional user-supplied input fields for this line
+  // (e.g. engraving text, configurator notes), keyed by field name.
+  map<string, string> custom_fields = 28;
 }
 
 message RemoveItem { uint32 Id = 1; }
@@ -57,6 +64,13 @@ message RemoveLineItemMarking {
   uint32 id = 1;
 }
 
+// SetLineItemCustomFields sets/merges user-supplied custom input fields on an
+// existing cart line (the dict equivalent of a line item marking).
+message SetLineItemCustomFields {
+  uint32 id = 1;
+  map<string, string> custom_fields = 2;
+}
+
 message SubscriptionAdded {
     uint32 itemId = 1;
     string detailsId = 3;
@@ -89,6 +103,7 @@ message Mutation {
     LineItemMarking line_item_marking = 6;
     RemoveLineItemMarking remove_line_item_marking = 7;
     SubscriptionAdded subscription_added = 8;
+    SetLineItemCustomFields set_line_item_custom_fields = 9;
     AddVoucher add_voucher = 20;
     RemoveVoucher remove_voucher = 21;
     UpsertSubscriptionDetails upsert_subscription_details = 22;