mail/tidemail: Add port
This is a Go-based MUA with a nice (and themeable!) TUI that supports
many modern MUA features like unified inbox, OAUTH (Gmail support is
currently halfway there, making its way through the Google approval
process), contact lists, searching, native tagging, and more. It also
supports (but does not mandate) hooks for text-generating (or text-
massaging) LLMs.