Refactor Record's internal representation

This commit refactors the internal representation of `BoundKind::Record`
to store a `RecordLayout` and a `Vec` of values, rather than a `Vec` of
key-value pairs. This change simplifies the representation and improves
efficiency by decoupling the record's structure from its specific values
during compilation and analysis.

The `RecordLayout` now defines the structure of the record, and the
values are stored in a separate vector, ordered according to the layout.
This allows for better optimization and type checking, as the record's
shape is explicitly defined and immutable once created.

src/ast/compiler/optimizer/folder.rs

@@ -50,27 +50,21 @@ impl<'a> Folder<'a> {
 
     pub fn try_fold_record(
         &self,
-        fields: &[(AnalyzedNode, AnalyzedNode)],
+        layout: &std::sync::Arc<RecordLayout>,
+        values: &[AnalyzedNode],
         template: &AnalyzedNode,
     ) -> Option<AnalyzedNode> {
-        let mut layout_fields = Vec::with_capacity(fields.len());
-        let mut values = Vec::with_capacity(fields.len());
+        let mut constant_values = Vec::with_capacity(values.len());
 
-        for (k_node, v_node) in fields {
-            if let BoundKind::Constant(Value::Keyword(kw)) = &k_node.kind {
-                if let BoundKind::Constant(val) = &v_node.kind {
-                    layout_fields.push((*kw, val.static_type()));
-                    values.push(val.clone());
-                } else {
-                    return None;
-                }
+        for v_node in values {
+            if let BoundKind::Constant(val) = &v_node.kind {
+                constant_values.push(val.clone());
             } else {
                 return None;
             }
         }
 
-        let layout = RecordLayout::get_or_create(layout_fields);
-        let record_val = Value::Record(layout, Rc::new(values));
+        let record_val = Value::Record(layout.clone(), Rc::new(constant_values));
         Some(self.make_constant_node(record_val, template))
     }