FR: Allow authenticating with an authkey from the OAuth web UI

[amluto]

What are you trying to do?

I want to add a device to my tailnet using an authkey. To do this, I need to figure out how to get command line access to the tailscale command line on that device, and this is annoying on basically everything except a standard MacOS or Linux install. (Annoying on Windows? Check. Annoying when I'm using an otherwise very pleasant containerized tailscale on some other system? Check.) Then I need to copy and paste the key, and pasting into a terminal can be annoying.

How should we solve this?

The landing page for the web authentication flow could offer an option like "Connect using an auth key".

For an even slicker experience, there could be a way to create a single-use authkey or otherwise directly add a non-user-associated device from that page, but that would be a more complex UI to get right.

What is the impact of not solving this?

I'm currently working around the issue by doing obnoxious things like docker exec -it [gobbledygook] tailscale --auth-key blah. This is no fun, and tailscale is otherwise very enjoyable to use! (It's extra un-fun because various people who package tailscale up into a container don't always agree where tailscale should live inside the container.)

Anything else?

No response