LibDevTools: Introduce a Firefox DevTools server library

To aid with debugging web page issues in Ladybird without needing to
implement a fully fledged inspector, we can implement the Firefox
DevTools protocol and use their DevTools. The protocol is described
here:

https://firefox-source-docs.mozilla.org/devtools/backend/protocol.html

This commit contains just enough to connect to Ladybird from a DevTools
client.

Libraries/LibDevTools/Actors/ProcessActor.cpp

@@ -0,0 +1,45 @@
+/*
+ * Copyright (c) 2025, Tim Flynn <trflynn89@ladybird.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <AK/JsonObject.h>
+#include <LibDevTools/Actors/ProcessActor.h>
+
+namespace DevTools {
+
+NonnullRefPtr<ProcessActor> ProcessActor::create(DevToolsServer& devtools, ByteString name, ProcessDescription description)
+{
+    return adopt_ref(*new ProcessActor(devtools, move(name), move(description)));
+}
+
+ProcessActor::ProcessActor(DevToolsServer& devtools, ByteString name, ProcessDescription description)
+    : Actor(devtools, move(name))
+    , m_description(move(description))
+{
+}
+
+ProcessActor::~ProcessActor() = default;
+
+void ProcessActor::handle_message(StringView type, JsonObject const&)
+{
+    send_unrecognized_packet_type_error(type);
+}
+
+JsonObject ProcessActor::serialize_description() const
+{
+    JsonObject traits;
+    traits.set("watcher"sv, m_description.is_parent);
+    traits.set("supportsReloadDescriptor"sv, true);
+
+    JsonObject description;
+    description.set("actor"sv, name());
+    description.set("id"sv, m_description.id);
+    description.set("isParent"sv, m_description.is_parent);
+    description.set("isWindowlessParent"sv, m_description.is_windowless_parent);
+    description.set("traits"sv, move(traits));
+    return description;
+}
+
+}