fix: add missing StackWrap enum and fields to kiwi schema (#166)

The kiwi binary encoder silently drops layoutWrap (flex-wrap) and
counterAxisSpacing (row-gap) because they were missing from the
schema definition. The serialize/deserialize code already handles
these values correctly — only the schema was incomplete.

Adds:
- StackWrap enum (NO_WRAP, WRAP)
- stackWrap field (476) to NodeChange
- stackCounterSpacing field (477) to NodeChange
- STRETCH value (4) to StackAlign enum

Fixes open-pencil/open-pencil#165

packages/core/src/kiwi/schema.ts

@@ -314,6 +314,7 @@ enum StackAlign {
   CENTER = 1;
   MAX = 2;
   BASELINE = 3;
+  STRETCH = 4;
 }
 
 enum StackCounterAlign {
@@ -343,6 +344,11 @@ enum StackPositioning {
   ABSOLUTE = 1;
 }
 
+enum StackWrap {
+  NO_WRAP = 0;
+  WRAP = 1;
+}
+
 enum ConnectionType {
   NONE = 0;
   INTERNAL_NODE = 1;
@@ -1506,6 +1512,8 @@ message NodeChange {
   float gridColumnGap = 438;
   GridTrackSize[] gridColumnSizes = 474;
   GridTrackSize[] gridRowSizes = 475;
+  StackWrap stackWrap = 476;
+  float stackCounterSpacing = 477;
 }
 
 message VideoPlayback {