Feature: clicking on @username in content should open user profile via your own instance

[patrickmcurry]

If I'm surfing the Fediverse on a Shuttlecraft instance, and I see someone mention @username (or @username@example.instance ), when I click on the username, I'd like to see that user's profile through the lens of my current instance. IE, instead of going to a URL like:

https://example.instance/@username

I'd like it to open this URL:

https://my.shuttlecraft.instance/private/profile/benbrown@hackers.town