add lists & VM memory limits

crates/haku/src/value.rs

@@ -105,6 +105,7 @@ impl RefId {
 #[derive(Debug, Clone)]
 pub enum Ref {
     Closure(Closure),
+    List(List),
     Shape(Shape),
     Scribble(Scribble),
 }
@@ -143,6 +144,11 @@ pub struct Closure {
     pub captures: Vec<Value>,
 }
 
+#[derive(Debug, Clone, PartialEq)]
+pub struct List {
+    pub elements: Vec<Value>,
+}
+
 #[derive(Debug, Clone)]
 pub enum Shape {
     Point(Vec4),