[proggeramlug]

Summary

Implements same-process MessageChannel / MessagePort delivery and the
worker_threads transfer/clone marker helpers.

Closes #3157
Closes #3159

Implementation

#3157 — MessageChannel ports + receiveMessageOnPort

• new MessageChannel() now returns a real heap object { port1, port2 }
  backed by a same-process paired-port registry (MESSAGE_PORTS keyed by a
  monotonic port id). Each port object carries closure-valued
  postMessage / on / addListener / once / off / removeListener /
  close / start / ref / unref / hasRef, each capturing its port id.
• port.postMessage(v) JSON-serializes v (structured-clone-like value
  semantics, matching the existing parentPort stdin/stdout IPC path) and
  enqueues it on the peer port's inbox.
• receiveMessageOnPort(port) synchronously pops one queued message and
  returns { message: value }, or undefined when the inbox is empty.
• port.on('message', cb) registers a listener and starts the port; the
  event-loop pump (js_worker_threads_channels_process_pending) drains
  inboxes and invokes listeners on the main thread. port.close() queues a
  close event on the port. The pump's "has active handles" check keeps the
  loop alive while a started port has queued messages or a pending close.
• Listener closures are GC-rooted + rewritten across moves via the existing
  worker_threads mutable root scanner.

#3159 — transfer / clone markers

• markAsUncloneable(obj) now records the object; port.postMessage of a
  marked-uncloneable value throws a DataCloneError.
  (markAsUntransferable / isMarkedAsUntransferable were already
  implemented.)

HIR lowering

• new MessageChannel() via named import now routes to the same
  receiver-less worker_threads NativeMethodCall as the
  new worker_threads.MessageChannel() member form, so the runtime allocates
  the real { port1, port2 } object instead of an empty user-class object.
• chan.port1 / chan.port2 on a MessageChannel-typed value lower to a
  plain object field read (returning the port object) rather than a zero-arg
  native getter. parentPort stays on its native-receiver dispatch path.

No new HIR variants added.

Validation

Gap test test-files/test_gap_worker_channels_3157plus.ts (MessageChannel
sync receiveMessageOnPort, async on('message') delivery, port close, and
the marker helpers) is byte-identical to
node --experimental-strip-types under the default auto-optimize compile.

./scripts/check_file_size.sh, cargo fmt --all -- --check, and
cargo test -p perry-hir are green.