Add reservation code to the information displayed at the top of a conversation thread

The code is important information used in other communication with guests (phone, WhatsApp, etc.), invoices, payment forms, etc. To get this information, a user must go to a thread or the calendar and click Details. This information should be more prominent, added alongside the guest name and email address. It could also be displayed in the inbox, alongside a guests' name, especially since the inbox can be searched by res code.