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_ir/src/contract.rs

@@ -30,7 +30,13 @@ impl Inst {
             | OpCode::COMPOUND_MEMBER_MUL
             | OpCode::COMPOUND_MEMBER_DIV
             | OpCode::COMPOUND_MEMBER_MOD
-            | OpCode::COMPOUND_MEMBER_EXP => reg_of(&self.a),
+            | 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 => reg_of(&self.a),
             // 无 def：控制流 / 写共享状态 / 纯写对象
             OpCode::HALT
             | OpCode::RETURN
@@ -139,7 +145,13 @@ impl Inst {
             | 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 => {
                 push_operand(&mut uses, &self.rd);
                 push_operand(&mut uses, &self.a);
                 push_operand(&mut uses, &self.b);
@@ -290,6 +302,10 @@ impl Inst {
             | OpCode::PROFILE_CALL
             | OpCode::FORK
             | OpCode::JOIN => {}
+            // TO_OBJECT：rd 原地转换（读且写）
+            OpCode::TO_OBJECT => {
+                push_operand(&mut uses, &self.rd);
+            }
         }
         uses
     }

crates/oxide_ir/src/inst.rs

@@ -94,6 +94,36 @@ impl Inst {
         Self::with_ext(OpCode::COMPOUND_MEMBER_EXP, obj, val, key, &[0, 0, 0])
     }
 
+    /// 成员复合赋值按位与：`obj[key] &= val`。
+    pub fn compound_member_bit_and(obj: Operand, val: Operand, key: Operand) -> Self {
+        Self::with_ext(OpCode::COMPOUND_MEMBER_BIT_AND, obj, val, key, &[0, 0, 0])
+    }
+
+    /// 成员复合赋值按位或：`obj[key] |= val`。
+    pub fn compound_member_bit_or(obj: Operand, val: Operand, key: Operand) -> Self {
+        Self::with_ext(OpCode::COMPOUND_MEMBER_BIT_OR, obj, val, key, &[0, 0, 0])
+    }
+
+    /// 成员复合赋值按位异或：`obj[key] ^= val`。
+    pub fn compound_member_bit_xor(obj: Operand, val: Operand, key: Operand) -> Self {
+        Self::with_ext(OpCode::COMPOUND_MEMBER_BIT_XOR, obj, val, key, &[0, 0, 0])
+    }
+
+    /// 成员复合赋值左移：`obj[key] <<= val`。
+    pub fn compound_member_shl(obj: Operand, val: Operand, key: Operand) -> Self {
+        Self::with_ext(OpCode::COMPOUND_MEMBER_SHL, obj, val, key, &[0, 0, 0])
+    }
+
+    /// 成员复合赋值右移：`obj[key] >>= val`。
+    pub fn compound_member_shr(obj: Operand, val: Operand, key: Operand) -> Self {
+        Self::with_ext(OpCode::COMPOUND_MEMBER_SHR, obj, val, key, &[0, 0, 0])
+    }
+
+    /// 成员复合赋值无符号右移：`obj[key] >>>= val`。
+    pub fn compound_member_ushr(obj: Operand, val: Operand, key: Operand) -> Self {
+        Self::with_ext(OpCode::COMPOUND_MEMBER_USHR, obj, val, key, &[0, 0, 0])
+    }
+
     // ── Call 系：ext = [nargs] ──
 
     /// 普通函数调用：rd=callee，a=this，b=首参，ext=\[nargs\]。参数从 `first_arg` 起连续占 nargs 个寄存器。