feat: JsObject 新增 frozen/sealed 标志位，修复 freeze/seal/preventExtensions/isFrozen/isSealed/isExtensible 六个完整性方法

crates/oxide_builtins/tests/object_integrity_tests.rs

@@ -0,0 +1,59 @@
+use oxide_types::object::JsObject;
+use oxide_types::value::JsValue;
+
+fn new_obj() -> JsObject {
+    JsObject::new_empty(0, JsValue::null())
+}
+
+#[test]
+fn test_set_frozen() {
+    let mut obj = new_obj();
+    assert!(!obj.is_frozen());
+    obj.set_frozen(true);
+    assert!(obj.is_frozen());
+}
+
+#[test]
+fn test_set_sealed() {
+    let mut obj = new_obj();
+    assert!(!obj.is_sealed());
+    obj.set_sealed(true);
+    assert!(obj.is_sealed());
+}
+
+#[test]
+fn test_frozen_and_sealed_independent() {
+    let mut obj = new_obj();
+    obj.set_frozen(true);
+    assert!(obj.is_frozen());
+    assert!(!obj.is_sealed());
+    obj.set_sealed(true);
+    assert!(obj.is_frozen());
+    assert!(obj.is_sealed());
+    obj.set_frozen(false);
+    assert!(!obj.is_frozen());
+    assert!(obj.is_sealed());
+}
+
+#[test]
+fn test_defaults_are_false() {
+    let obj = new_obj();
+    assert!(!obj.is_frozen());
+    assert!(!obj.is_sealed());
+}
+
+#[test]
+fn test_clear_frozen() {
+    let mut obj = new_obj();
+    obj.set_frozen(true);
+    obj.set_frozen(false);
+    assert!(!obj.is_frozen());
+}
+
+#[test]
+fn test_clear_sealed() {
+    let mut obj = new_obj();
+    obj.set_sealed(true);
+    obj.set_sealed(false);
+    assert!(!obj.is_sealed());
+}