PostMessageTransport: make debug logging opt-in (or accept a logger)

El issue apunta a src/message-transport.ts, específicamente a las líneas donde se llama a console.debug. Comience examinando el constructor de PostMessageTransport y su firma actual. La tarea consiste en agregar un tercer argumento opcional para un logger, que por defecto no registre nada. Verifique cómo se instancia el transporte en otras partes del código base para garantizar la compatibilidad con versiones anteriores. Escriba una prueba para verificar que el registro solo ocurra cuando se proporciona un logger.

Problem

PostMessageTransport calls console.debug unconditionally (src/message-transport.ts at 264d9ca, lines 77, 82, 87 and 128):

• "Sending message" for every outgoing message except tool-input-partial
• "Parsed message" for every valid incoming message
• "Ignoring message from unknown source" for every message from another frame

A host cannot turn these off. The transport takes no option for it, and the only workaround is wrapping console.debug globally.

The noise grows with the number of Apps on a page. Each card's host transport listens on the same window, so a message from any View reaches every bridge. The owning bridge logs "Parsed message", and each of the other N−1 bridges logs "Ignoring message from unknown source" with the full MessageEvent. With four cards in a conversation, every View message produces four host lines, plus the View's own "Sending message" inside its frame. Size changes and host-context updates fan out the same way.

The source check is correct. Only the logging is the problem.

Prior discussion

• #237 / #239 moved the unknown-source log from console.error to console.debug.
• #546 skipped the log for tool-input-partial because it flooded the console.
• #741 asked for opt-in logging or a configurable logger, and noted that full payloads, including tool-result _meta, reach the console. Its filer closed it without a change.

Proposal

Make transport logging opt-in through an options argument:

new PostMessageTransport(eventTarget, eventSource, { logger?: Pick<Console, "debug"> })

Log nothing when logger is absent. The console.error for a malformed JSON-RPC message can stay. The third argument keeps the existing constructor compatible.

Happy to open a PR if this direction works.

Seen on 1.7.5; unchanged on main as of v2.0.0.