Expose Airbnb Additional Guests Array via Public API/MCP

Currently, the Public API and MCP only expose the primary guest for Airbnb reservations and conversations. However, the Hospitable web application has access to the full array of named additional guests.

The request is to expose this same array of named additional guests through a supported Public API endpoint or MCP method, allowing developers to retrieve all guest names associated with a thread rather than just the primary booker.