CLI: make it easier to find the config files and the tokens

Target component

• CLI
• SDK
• Something else
• Not sure

Overview

There used to be a --show-token flag on oxide auth status (added in https://github.com/oxidecomputer/oxide.rs/pull/48). There is not anymore, which means that if I use the CLI to get a token to use in one of the SDKs, the only way I can find out what that token is is to go and find credentials.toml. The location of that file is described in the docs but there is no way in the CLI itself to find out where it is.

I've updated the README for the TS client to explain where the credentials file is, so maybe that is most of the solution, but I think it would also help for someone who is working in the CLI but not looking at the docs to have a way to get to an answer to these questions. Some ideas:

• a command that prints the location of the config
• a flag on auth status that prints the tokens
• flag documentation mention what the default location is, like how --user-config-file below says default: ~/.config/nextest/config.toml or platform equivalent.

Implementation details

No response

Anything else you would like to add?

No response

Start with the existing oxide auth status command and the --user-config-file help text. Review the linked configuration-file documentation and the prior --show-token change to understand current behavior. Done should provide a clear CLI path to the configuration location and token guidance, with the chosen interface documented.