feat(runtime): native MessagePort, MessageChannel, BroadcastChannel, and node:worker_threads

Ports are Node's three-way split without libuv: an isolate-free PortData
(mutex-guarded queue, sibling-group entanglement) under a per-isolate
NativeMessagePort whose wake is a coalesced EventLoop::PostInternal —
producers never take a foreign isolate's Locker. Pairwise channels and
named BroadcastChannel groups share one SiblingGroup mechanism; close
sentinels are empty messages ordered behind queued traffic.

Ports transfer through postMessage and structuredClone as host-object
tag 2 on the DOMException wire format: index in-stream, PortData
out-of-band, nothing detached until the whole graph has written, and
received ports pre-constructed before ReadValue since no JS may run
inside ReadHostObject. In passing this fixes claimed host objects
suppressing V8's embedder-field detection (ObjC wrappers were written
as plain objects once any DOMException existed) and a dangling handle
in Deserialize's ports out-parameter.

Worker and the worker global scope are now real EventTargets: delivery
dispatches MessageEvents through defineEventHandler-backed onmessage
attributes (position-fixed HTML handler semantics), replacing the
direct property calls. Handler wrappers live on the target's own
listener bag — a WeakMap keyed by ObjectManager-registered objects
corrupts the heap when the finalizer resurrects them.

node:worker_threads ships the real MessageChannel/MessagePort/
BroadcastChannel/receiveMessageOnPort/threadId/environment-data
surface with documented shims for the rest (docs/worker-threads.md).
New globals ride the lazy tier: MessagePort, MessageChannel,
BroadcastChannel, MessageEvent.

Suite: 1664/0 (+154 messaging specs in the shared submodule).

Author: edusperoni

NativeScript/runtime/LazyGlobals.cpp

@@ -3,6 +3,7 @@
 #include "Base64.h"
 #include "BuiltinLoader.h"
 #include "Helpers.h"
+#include "Messaging.h"
 #include "StructuredSerialization.h"
 #include "TextEncoding.h"
 
@@ -39,6 +40,11 @@ constexpr LazyGlobalEntry kLazyGlobals[] = {
     // events.js is an eager builtin (Events::Init), so this row never runs a
     // file: the read hits the exports cache and only the placement is lazy.
     {"CustomEvent", "CustomEvent", BuiltinExports<BuiltinId::kEvents>},
+    {"MessageEvent", "MessageEvent", BuiltinExports<BuiltinId::kMessageEvent>},
+    {"MessagePort", "MessagePort", messaging::GetMessageChannelExports},
+    {"MessageChannel", "MessageChannel", messaging::GetMessageChannelExports},
+    {"BroadcastChannel", "BroadcastChannel",
+     messaging::GetBroadcastChannelExports},
 };
 
 void LazyGlobalGetter(Local<v8::Name> property,