Decide what to do about the mail subsystem

Switch between MAIL and BULLETIN modes? MAIL commands are documented here.

Instead of making MAIL and FORWARD the same, why not have "MAIL" enter a mail mode where you can read mails.

Alternatively, make "mail" just a folder like any other except set to private and make th e owner that user. Maybe have a leading colon that CREATE can't use.

Or... just get rid of the mail bit.

Or... tie it into actual smtp mail.