LibJS: Implement the AsyncDisposableStack interface

This is very similar to the DisposableStack interface, except disposal
of resources is promise-based.

Libraries/LibJS/Runtime/AsyncDisposableStack.h

@@ -0,0 +1,41 @@
+/*
+ * Copyright (c) 2025, Tim Flynn <trflynn89@ladybird.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <LibJS/Runtime/AbstractOperations.h>
+#include <LibJS/Runtime/Object.h>
+
+namespace JS {
+
+class AsyncDisposableStack final : public Object {
+    JS_OBJECT(AsyncDisposableStack, Object);
+    GC_DECLARE_ALLOCATOR(AsyncDisposableStack);
+
+public:
+    virtual ~AsyncDisposableStack() override = default;
+
+    enum class AsyncDisposableState {
+        Pending,
+        Disposed
+    };
+
+    [[nodiscard]] AsyncDisposableState async_disposable_state() const { return m_async_disposable_state; }
+    void set_disposed() { m_async_disposable_state = AsyncDisposableState::Disposed; }
+
+    [[nodiscard]] DisposeCapability const& dispose_capability() const { return m_dispose_capability; }
+    [[nodiscard]] DisposeCapability& dispose_capability() { return m_dispose_capability; }
+
+private:
+    AsyncDisposableStack(DisposeCapability, Object& prototype);
+
+    virtual void visit_edges(Visitor& visitor) override;
+
+    DisposeCapability m_dispose_capability;
+    AsyncDisposableState m_async_disposable_state { AsyncDisposableState::Pending };
+};
+
+}