In TricepMail, messages to e.g. [email protected] versus [email protected] are separated in the UI, and you can configure the "ignore" mailbox to block all incoming messages. You can also setup mailboxes that accept messages from specific senders only.
TricepMail also has everything (and a bit more) that you've listed under "Web interface". TricepMail isn't meant to be used for trash/throwaways, but you can use it for that if you want. It's meant to compartmentalize real email for the demands of today, especially for things like the FCC requiring email addresses on applications.
For example, I would consider incoming email from the FCC to be extremely important (definitely not trash), but I wouldn't want to use my usual personal email address for this. I would still want to see it without going through all the hassle of setting up a separate email server and/or using a separate email client. I want everything in one simple, organized place. This is why I created TricepMail.
I've starred your repo. Looking forward to seeing its progress. :)