Clicking on @user in messages/notifications navigates you away from the site

It would be better to always link to the shadow copy of their profile on the local instance instead of sending the user off the site. This behavior currently is confusing and frankly silly.

This image should clarify what's going on. Our parsing of @username in a message is producing the wrong URL. We want the behavior of clicking on /users/1234 not /users/lain or a URL to the user's profile on the remote server.