Feature Request: Chat - Show Presence

My apologies if there is either an existing feature or an existing feature request - I can find neither.

I really like the GUI chat interface, however fundamental to the utility of such chat is being able to determine the **presence** of other parties to the chat. We've all seen this in other chat apps - a green dot for available, yellow for offline, red for busy...yadahyadah.

The real requirement is pretty simple: Show me whether the other party is online and available to chat. Without presence, I might as well send them an encrypted email and they can respond whenever they like. Without presence if I want to communicate with someone **now** then I either have to send them a chat and see if they respond or simply call them on the phone. With presence I can choose to chat if they show as online or otherwise choose to call them if it's urgent.

Presence makes the whole thing more functional.

Once again, apologies if this is already covered.

The issue describes adding online-availability presence to the GUI chat, but names no files, tests, or entry points. Start by locating the chat UI and presence-related client/server code; done would mean users can see whether another party is online and available to chat.

Written by the indexing model from the issue text.