fix: lazy select_with_default

nix-js/tests/operators.rs

@@ -99,3 +99,21 @@ fn logical_not() {
     assert_eq!(eval("!true"), Value::Bool(false));
     assert_eq!(eval("!false"), Value::Bool(true));
 }
+
+#[test]
+fn select_with_default_lazy_evaluation() {
+    assert_eq!(eval("{ a = 1; }.a or (1 / 0)"), Value::Int(1));
+}
+
+#[test]
+fn select_with_default_nested_lazy() {
+    assert_eq!(
+        eval("{ a.b = 42; }.a.b or (builtins.abort \"should not evaluate\")"),
+        Value::Int(42)
+    );
+}
+
+#[test]
+fn select_with_default_fallback() {
+    assert_eq!(eval("{ a = 1; }.b or 999"), Value::Int(999));
+}