Describe the bug

If you're trying Goose with a xAI API key, set your XAI_HOST='https://api.x.ai/v1/' env var with a trailing slash. The code with throw a 404 error if you use the default HOST in Goose and just specify the API key.

Probably in './crates/goose/src/providers/xai.rs' the code is intended to
.response_post("/chat/completions", &payload)
instead of the current
.response_post("chat/completions", &payload)