fix: csg color loss for non-intersecting union (#287)

patches/@jscad+modeling+2.9.6.patch

@@ -222,7 +222,7 @@ index cf9c591..af1842c 100644
  }
 
 diff --git a/node_modules/@jscad/modeling/src/operations/booleans/unionGeom3Sub.js b/node_modules/@jscad/modeling/src/operations/booleans/unionGeom3Sub.js
-index a4026e3..3dc6158 100644
+index a4026e3..2ac0689 100644
 --- a/node_modules/@jscad/modeling/src/operations/booleans/unionGeom3Sub.js
 +++ b/node_modules/@jscad/modeling/src/operations/booleans/unionGeom3Sub.js
 @@ -14,8 +14,8 @@ const unionSub = (geometry1, geometry2) => {
@@ -236,3 +236,14 @@ index a4026e3..3dc6158 100644
 
    a.clipTo(b, false)
    // b.clipTo(a, true); // ERROR: doesn't work
+@@ -32,8 +32,8 @@ const unionSub = (geometry1, geometry2) => {
+ // Like union, but when we know that the two solids are not intersecting
+ // Do not use if you are not completely sure that the solids do not intersect!
+ const unionForNonIntersecting = (geometry1, geometry2) => {
+-  let newpolygons = geom3.toPolygons(geometry1)
+-  newpolygons = newpolygons.concat(geom3.toPolygons(geometry2))
++  let newpolygons = geom3.toPolygons(geometry1, true)
++  newpolygons = newpolygons.concat(geom3.toPolygons(geometry2, true))
+   return geom3.create(newpolygons)
+ }
+