feat: 实现 new String 装箱构造 + String.prototype.toString，补齐 boxed primitives

crates/oxide_vm/tests/builtins_boolean_tests.rs

@@ -136,3 +136,16 @@ fn boolean_boxes_participate_in_numeric_coercion() {
     let r = eval(&mut vm, "new Boolean(false) | 0").unwrap();
     assert_eq!(r.as_int(), 0);
 }
+
+#[test]
+fn boxed_boolean_valueof_tostring_and_object_e2e() {
+    let mut vm = Vm::new();
+    assert!(!eval(&mut vm, "new Boolean(false).valueOf()").unwrap().as_bool());
+    assert!(eval(&mut vm, "new Boolean(1).valueOf()").unwrap().as_bool());
+
+    let t = eval(&mut vm, "new Boolean(false).toString()").unwrap();
+    assert_eq!(str_val(&vm, t), "false");
+
+    let ty = eval(&mut vm, "typeof new Boolean(true)").unwrap();
+    assert_eq!(str_val(&vm, ty), "object");
+}

crates/oxide_vm/tests/builtins_number_tests.rs

@@ -135,3 +135,28 @@ fn number_static_constants_remain_bound() {
     assert_eq!(eval(&mut vm, "Number.MAX_SAFE_INTEGER").unwrap().as_double(), 9007199254740991f64);
     assert!(eval(&mut vm, "Number.POSITIVE_INFINITY > 0").unwrap().as_bool());
 }
+
+#[test]
+fn boxed_number_valueof_preserves_int_and_float() {
+    let mut vm = Vm::new();
+    let i = eval(&mut vm, "new Number(5).valueOf()").unwrap();
+    assert!(i.is_int());
+    assert_eq!(i.as_int(), 5);
+
+    let f = eval(&mut vm, "new Number(1.5).valueOf()").unwrap();
+    assert!(f.is_double());
+    assert_eq!(f.as_double(), 1.5);
+
+    let s = eval(&mut vm, "new Number('7').valueOf()").unwrap();
+    assert_eq!(s.as_int(), 7);
+}
+
+#[test]
+fn boxed_number_is_object_and_call_stays_primitive() {
+    let mut vm = Vm::new();
+    let ty = eval(&mut vm, "typeof new Number(5)").unwrap();
+    assert_eq!(vm.kernel_core().string_forge().lookup(ty.as_string_index()).unwrap(), "object");
+
+    let n = eval(&mut vm, "Number('7')").unwrap();
+    assert_eq!(n.as_int(), 7);
+}

crates/oxide_vm/tests/builtins_string_tests.rs

@@ -240,3 +240,33 @@ fn string_replace_all() {
     let result = eval(&mut vm, "'aba'.replaceAll('a', 'c')").unwrap();
     assert_eq!(to_str(&vm, result), "cbc");
 }
+
+#[test]
+fn boxed_string_valueof_and_tostring() {
+    let mut vm = Vm::new();
+    let v = eval(&mut vm, "new String('abc').valueOf()").unwrap();
+    assert!(v.is_string());
+    assert_eq!(to_str(&vm, v), "abc");
+
+    let t = eval(&mut vm, "new String('abc').toString()").unwrap();
+    assert!(t.is_string());
+    assert_eq!(to_str(&vm, t), "abc");
+}
+
+#[test]
+fn boxed_string_is_object_and_empty_default() {
+    let mut vm = Vm::new();
+    let ty = eval(&mut vm, "typeof new String('x')").unwrap();
+    assert_eq!(to_str(&vm, ty), "object");
+
+    let empty = eval(&mut vm, "new String().valueOf()").unwrap();
+    assert_eq!(to_str(&vm, empty), "");
+}
+
+#[test]
+fn string_call_conversion_stays_primitive() {
+    let mut vm = Vm::new();
+    let v = eval(&mut vm, "String(123)").unwrap();
+    assert!(v.is_string());
+    assert_eq!(to_str(&vm, v), "123");
+}