Feature request: implement the inbox

[redbrain]

What do you want

An inbox feature, like the one currently seen in Discord. Allows you to see your most recent messages or mentions and mark them as read or jump to their channel.

Why

I use the inbox constantly to catch up on multiple conversations, and implementation in Cordless would be nice.

Implementation hints

I don't know what keys are still available, but you could probably toggle the inbox on/off in one of the existing panes. The only other keys needed are mark channel as read, mark all as read, jump to channel, and toggle messages/mentions