feat: with 语句、成员位/移位复合赋值、CALL_NATIVE 无目标修复

with 语句：新增 emit 支持，with 体内自由标识符动态解析（对象属性优先，
回退外层），支持读/写/复合赋值/自增自减/delete/var 初始化动态化，
TO_OBJECT opcode 处理原始值对象，顶层 this 绑定全局对象。

复合赋值：新增 6 个 COMPOUND_MEMBER_BIT_* opcode 支持成员位/移位复合赋值，
修复 computed member 复合赋值覆盖 bug，with 内标识符复合赋值动态化。

CALL_NATIVE：实现全局 isNaN/isFinite 并绑定，用户覆盖 builtin 名时
回退通用调用路径而非报错，局部遮蔽 builtin 名走普通 CALL。

test262: with 34 pass（基线 0），compound-assignment 320 pass（基线 223）

crates/oxide_vm/src/vm.rs

@@ -1305,6 +1305,10 @@ impl Vm {
                     self.dispatch_typeof(rd, a);
                 }
 
+                OpCode::TO_OBJECT => {
+                    self.dispatch_to_object(rd)?;
+                }
+
                 OpCode::VOID => {
                     self.dispatch_void(rd);
                 }
@@ -1374,7 +1378,13 @@ impl Vm {
                 | OpCode::COMPOUND_MEMBER_MUL
                 | OpCode::COMPOUND_MEMBER_DIV
                 | OpCode::COMPOUND_MEMBER_MOD
-                | OpCode::COMPOUND_MEMBER_EXP => {
+                | OpCode::COMPOUND_MEMBER_EXP
+                | OpCode::COMPOUND_MEMBER_BIT_AND
+                | OpCode::COMPOUND_MEMBER_BIT_OR
+                | OpCode::COMPOUND_MEMBER_BIT_XOR
+                | OpCode::COMPOUND_MEMBER_SHL
+                | OpCode::COMPOUND_MEMBER_SHR
+                | OpCode::COMPOUND_MEMBER_USHR => {
                     self.dispatch_member_op(op, rd, a, b)?;
                 }