perf: run 签名改 &Arc<CompiledModule>，顶层模块跨 run 共享——collect_flat_modules 顶层改 Arc::clone 消除逐 run 常量池深拷贝，全调用点 Arc 包装迁移

crates/oxide_vm/tests/builtins_array_buffer_tests.rs

@@ -1,3 +1,5 @@
+use std::sync::Arc;
+
 use oxide_compiler::compiler::Compiler;
 use oxide_types::value::JsValue;
 use oxide_vm::vm::Vm;
@@ -6,7 +8,7 @@ fn eval(vm: &mut Vm, source: &str) -> Result<JsValue, String> {
     let allocator = oxide_parser::Allocator::default();
     let program = oxide_parser::parse(&allocator, source).map_err(|e| format!("Parse error: {:?}", e))?;
     let module = Compiler::new().compile(&program).map_err(|e| format!("Compile error: {}", e))?;
-    vm.run(&module)
+    vm.run(&Arc::new(module))
 }
 
 fn to_str(vm: &Vm, val: JsValue) -> String {