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_tests.rs

@@ -1,3 +1,5 @@
+use std::sync::Arc;
+
 use oxide_builtins::array::{array_constructor, array_push};
 use oxide_compiler::compiler::Compiler;
 use oxide_types::value::JsValue;
@@ -8,7 +10,7 @@ fn eval(source: &str) -> Result<(Vm, JsValue), String> {
     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))?;
     let mut vm = Vm::new();
-    let result = vm.run(&module)?;
+    let result = vm.run(&Arc::new(module))?;
     Ok((vm, result))
 }