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/string.rs

@@ -1,7 +1,7 @@
 //! 标准库：string（split, trim, substring, replace, contains, upper, lower, starts_with, ends_with）
 
 use crate::error::RuntimeError;
-use crate::interpreter::{Interpreter, Value};
+use crate::interpreter::{Runtime, Value};
 use std::cell::RefCell;
 use std::rc::Rc;
 
@@ -19,7 +19,7 @@ fn require_string(val: &Value, arg_name: &str) -> Result<String, RuntimeError> {
 // split(str, delim) → array of substrings
 // ============================================================================
 
-pub fn split(_interp: &mut Interpreter, args: Vec<Value>) -> Result<Value, RuntimeError> {
+pub fn split(_interp: &mut dyn Runtime, args: Vec<Value>) -> Result<Value, RuntimeError> {
     if args.len() < 2 {
         return Err(RuntimeError::RuntimeError {
             message: "split() expects 2 arguments (string, delimiter)".into(),
@@ -43,7 +43,7 @@ pub fn split(_interp: &mut Interpreter, args: Vec<Value>) -> Result<Value, Runti
 // trim(str) → string with leading/trailing whitespace removed
 // ============================================================================
 
-pub fn trim(_interp: &mut Interpreter, args: Vec<Value>) -> Result<Value, RuntimeError> {
+pub fn trim(_interp: &mut dyn Runtime, args: Vec<Value>) -> Result<Value, RuntimeError> {
     if args.is_empty() {
         return Err(RuntimeError::RuntimeError {
             message: "trim() expects 1 argument (string)".into(),
@@ -58,7 +58,7 @@ pub fn trim(_interp: &mut Interpreter, args: Vec<Value>) -> Result<Value, Runtim
 // substring(str, start, len?) → substring
 // ============================================================================
 
-pub fn substring(_interp: &mut Interpreter, args: Vec<Value>) -> Result<Value, RuntimeError> {
+pub fn substring(_interp: &mut dyn Runtime, args: Vec<Value>) -> Result<Value, RuntimeError> {
     if args.is_empty() {
         return Err(RuntimeError::RuntimeError {
             message: "substring() expects at least 2 arguments (string, start, len?)".into(),
@@ -81,7 +81,7 @@ pub fn substring(_interp: &mut Interpreter, args: Vec<Value>) -> Result<Value, R
 // replace(str, old, new) → string with all occurrences replaced
 // ============================================================================
 
-pub fn replace(_interp: &mut Interpreter, args: Vec<Value>) -> Result<Value, RuntimeError> {
+pub fn replace(_interp: &mut dyn Runtime, args: Vec<Value>) -> Result<Value, RuntimeError> {
     if args.len() < 3 {
         return Err(RuntimeError::RuntimeError {
             message: "replace() expects 3 arguments (string, old, new)".into(),
@@ -106,7 +106,7 @@ pub fn replace(_interp: &mut Interpreter, args: Vec<Value>) -> Result<Value, Run
 // contains(str, needle) → bool
 // ============================================================================
 
-pub fn contains(_interp: &mut Interpreter, args: Vec<Value>) -> Result<Value, RuntimeError> {
+pub fn contains(_interp: &mut dyn Runtime, args: Vec<Value>) -> Result<Value, RuntimeError> {
     if args.len() < 2 {
         return Err(RuntimeError::RuntimeError {
             message: "contains() expects 2 arguments (string, needle)".into(),
@@ -122,7 +122,7 @@ pub fn contains(_interp: &mut Interpreter, args: Vec<Value>) -> Result<Value, Ru
 // upper(str) → uppercase (ASCII)
 // ============================================================================
 
-pub fn upper(_interp: &mut Interpreter, args: Vec<Value>) -> Result<Value, RuntimeError> {
+pub fn upper(_interp: &mut dyn Runtime, args: Vec<Value>) -> Result<Value, RuntimeError> {
     if args.is_empty() {
         return Err(RuntimeError::RuntimeError {
             message: "upper() expects 1 argument (string)".into(),
@@ -137,7 +137,7 @@ pub fn upper(_interp: &mut Interpreter, args: Vec<Value>) -> Result<Value, Runti
 // lower(str) → lowercase (ASCII)
 // ============================================================================
 
-pub fn lower(_interp: &mut Interpreter, args: Vec<Value>) -> Result<Value, RuntimeError> {
+pub fn lower(_interp: &mut dyn Runtime, args: Vec<Value>) -> Result<Value, RuntimeError> {
     if args.is_empty() {
         return Err(RuntimeError::RuntimeError {
             message: "lower() expects 1 argument (string)".into(),
@@ -152,7 +152,7 @@ pub fn lower(_interp: &mut Interpreter, args: Vec<Value>) -> Result<Value, Runti
 // starts_with(str, prefix) → bool
 // ============================================================================
 
-pub fn starts_with(_interp: &mut Interpreter, args: Vec<Value>) -> Result<Value, RuntimeError> {
+pub fn starts_with(_interp: &mut dyn Runtime, args: Vec<Value>) -> Result<Value, RuntimeError> {
     if args.len() < 2 {
         return Err(RuntimeError::RuntimeError {
             message: "starts_with() expects 2 arguments (string, prefix)".into(),
@@ -168,7 +168,7 @@ pub fn starts_with(_interp: &mut Interpreter, args: Vec<Value>) -> Result<Value,
 // ends_with(str, suffix) → bool
 // ============================================================================
 
-pub fn ends_with(_interp: &mut Interpreter, args: Vec<Value>) -> Result<Value, RuntimeError> {
+pub fn ends_with(_interp: &mut dyn Runtime, args: Vec<Value>) -> Result<Value, RuntimeError> {
     if args.len() < 2 {
         return Err(RuntimeError::RuntimeError {
             message: "ends_with() expects 2 arguments (string, suffix)".into(),