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/binder.rs

@@ -374,14 +374,28 @@ impl Binder {
             }
 
             UntypedKind::Record { fields } => {
-                let mut bound_fields = Vec::new();
+                let mut bound_values = Vec::new();
+                let mut layout_fields = Vec::new();
+
                 for (k, v) in fields {
-                    bound_fields.push((self.bind(k)?, self.bind(v)?));
+                    let key_node = self.bind(k)?;
+                    let val_node = self.bind(v)?;
+                    
+                    if let BoundKind::Constant(crate::ast::types::Value::Keyword(kw)) = key_node.kind {
+                        layout_fields.push((kw, crate::ast::types::StaticType::Any));
+                    } else {
+                        return Err(format!("Record keys must be keywords, found at {:?}", key_node.identity.location));
+                    }
+                    bound_values.push(val_node);
                 }
+
+                let layout = crate::ast::types::RecordLayout::get_or_create(layout_fields);
+
                 Ok(self.make_node(
                     node.identity.clone(),
                     BoundKind::Record {
-                        fields: bound_fields,
+                        layout,
+                        values: bound_values,
                     },
                 ))
             }