ulong and grid list wrapper test

- wrapped lists in serialized dicts do work, maybe wrap anything.
- note: maybe convert long fields to string fields to support ulong?

Runtime/SceneGrid.cs

@@ -1,4 +1,3 @@
-using System.Collections.Generic;
 using UnityEngine;
 
 namespace VertexColor.ScenePartition
@@ -14,16 +13,18 @@ namespace VertexColor.ScenePartition
 
         public SceneGridDictionary Grid => grid;
 
-        public void Insert(long scenePartitionId, Vector3 point)
+        public void Insert(ulong scenePartitionId, Vector3 point)
         {
             int gridId = CalculateGridPosition(point, cellSize);
-            if (grid.TryGetValue(gridId, out List<long> ids))
+            if (grid.TryGetValue(gridId, out GridList ids))
             {
-                ids.Add(scenePartitionId);
+                ids.list.Add(scenePartitionId);
             }
             else
             {
-                grid.Add(gridId, new List<long> { scenePartitionId });
+                var l = new GridList();
+                l.list.Add(scenePartitionId);
+                grid.Add(gridId, l);
             }
         }
 
@@ -64,5 +65,20 @@ namespace VertexColor.ScenePartition
 
             return (x, y);
         }
+
+        public static ulong ULongPairToULong(ulong x, ulong y)
+        {
+            // Combine x and y components into a single ulong
+            return (x << 32) | (uint)y;
+        }
+
+        public static (ulong, ulong) ULongToULongPair(ulong value)
+        {
+            // Extract x and y components from the combined ulong
+            ulong x = value >> 32;
+            ulong y = (uint)value;
+
+            return (x, y);
+        }
     }
 }