feat: 字节码VM基础设施 — 编译器、VM执行循环、Runtime trait

Phase 1-3: 基础VM架构
- 新增 Runtime trait: 抽象树遍历解释器和VM的共同接口
- NativeFn 改为接受 &mut dyn Runtime
- 重构所有内置函数使用新签名
- vm/opcode.rs: 33个字节码指令 + 编码/解码辅助函数
- vm/compiler.rs: AST→字节码编译器，支持变量解析、跳转回填、作用域
- vm/vm.rs: 栈式VM执行循环，支持全局变量、原生函数调用
- lib.rs: 新增 run_file_vm() + --vm CLI标志
- 修复: 跳转偏移计算、对象字面量编译

工作特性: 算术、变量、while/for循环、条件、数组、对象、字符串
待完成: 用户定义函数调用、闭包/upvalue捕获、完整require支持

Release模式: 1M算术循环 VM 0.44s vs 树遍历 0.89s (2.0x加速)

aster-core/src/interpreter/builtins/core.rs

@@ -1,9 +1,9 @@
 //! 标准库：core（len, typeof, push, pop）
 
 use crate::error::RuntimeError;
-use crate::interpreter::{Interpreter, Value};
+use crate::interpreter::{Runtime, Value};
 
-pub fn len(_interp: &mut Interpreter, args: Vec<Value>) -> Result<Value, RuntimeError> {
+pub fn len(_runtime: &mut dyn Runtime, args: Vec<Value>) -> Result<Value, RuntimeError> {
     if args.is_empty() {
         return Err(RuntimeError::RuntimeError {
             message: "len() expects 1 argument".into(),
@@ -21,7 +21,7 @@ pub fn len(_interp: &mut Interpreter, args: Vec<Value>) -> Result<Value, Runtime
     }
 }
 
-pub fn typeof_fn(_interp: &mut Interpreter, args: Vec<Value>) -> Result<Value, RuntimeError> {
+pub fn typeof_fn(_interp: &mut dyn Runtime, args: Vec<Value>) -> Result<Value, RuntimeError> {
     if args.is_empty() {
         return Err(RuntimeError::RuntimeError {
             message: "typeof() expects 1 argument".into(),
@@ -41,7 +41,7 @@ pub fn typeof_fn(_interp: &mut Interpreter, args: Vec<Value>) -> Result<Value, R
     Ok(Value::String(s.into()))
 }
 
-pub fn push(_interp: &mut Interpreter, args: Vec<Value>) -> Result<Value, RuntimeError> {
+pub fn push(_interp: &mut dyn Runtime, args: Vec<Value>) -> Result<Value, RuntimeError> {
     if args.len() < 2 {
         return Err(RuntimeError::RuntimeError {
             message: "push() expects 2 arguments (array, value)".into(),
@@ -61,7 +61,7 @@ pub fn push(_interp: &mut Interpreter, args: Vec<Value>) -> Result<Value, Runtim
     }
 }
 
-pub fn pop(_interp: &mut Interpreter, args: Vec<Value>) -> Result<Value, RuntimeError> {
+pub fn pop(_interp: &mut dyn Runtime, args: Vec<Value>) -> Result<Value, RuntimeError> {
     if args.is_empty() {
         return Err(RuntimeError::RuntimeError {
             message: "pop() expects 1 argument (array)".into(),