'[user] has reset their account!' dialog is confusing

I was trying to open someone's public KBFS directory, and this dialog popped up:

- The red message makes it feel like I should be wary of this, and consider the account possibly compromised. I feel like I should do something about this but I can't figure out what.
- The wording makes it sound like they maybe lost access to their private key that they were using when I tracked them, but I can't really tell if this really is the case.
- I don't know what the green and blue checkmarks mean, but the blue one is probably connected to the 'new' label on the left.
- The 'new' label itself doesn't tell me much either; if the account has been reset shouldn't all the proofs be new anyway? Is it a new linked account compared to the last time I tracked them? If it's really just telling me that, why is this information displayed in the account reset window?

Start with the account-reset dialog shown in the issue and review the surrounding discussion for the intended meaning of its warning, checkmarks, and “new” label. Trace where this dialog is presented, then define clearer wording and status explanations; the work is done when a user can understand the reset state and what action, if any, is expected.

Written by the indexing model from the issue text.