Add Vercel AI Gateway plugin provider

[robinebers]

Unconventional but I'd love to see how much I spent this month of my limit. Not sure if they expose this readily.

[jarvis-harssha]

+1 to this, i use vercel gateway to power all my ai apps, but yea idts they expose this?

[robinebers]

I experimented with this, but unfortunately Vercel exposes very little information.

https://vercel.com/docs/ai-gateway/capabilities/usage