Redirect unauthenticated users to canonical pages for remote profiles

[WesleyAC]

Pitch

I have a PR for upstream to redirect unauthenticated users to the canonical page for remote profiles (mastodon#25978), but they seem unlikely to look at the patch. I described the reasoning for this in glitch-soc#2225. It'll need a bit more work to get the benefits described there (changing the API as well as the UI), but I'm happy to do that if people want to apply the patch.

I would do this as a PR, but Github makes it impossible to have multiple forks of the same repo, or to make a PR from one fork to a different one, for reasons that are inscrutable to me :/

Motivation

See glitch-soc#2225

[pronoiac]

It might be worth noting that the requested functionality (or something adjacent) can be abused, leading to something like an open redirect; here's a blog post about it, which ... ugh, some of the examples work on my instance. Which I probably should file a separate issue about.