docs: Fix broken links in docs with lychee (#42404)

Lychee is a [Rust based](https://lychee.cli.rs) async parallel link
checker.

I ran it against the codebase to suss out stale links and fixed those
up.

There's currently 2 remaining cases that I don't know how to resolve:

1. https://flathub.org/apps/dev.zed.Zed - nginx is giving a 502 bad
gateway
2.
https://github.com/zed-industries/zed/actions/workflows/ci.yml/badge.svg
- I don't want to mess with the CI pipeline in this PR.

Once again, I'll punt to the Docs Czar to see if this gets incorporated
into CI later.

---

## Running `lychee` locally:

```
cargo binstall -y lychee
lychee .
```

---
Release Notes:

- N/A

Signed-off-by: mrg <miguelraz@ciencias.unam.mx>

docs/src/ai/llm-providers.md

@@ -587,7 +587,7 @@ These routing controls let you fine‑tune cost, capability, and reliability tra
 
 ### Vercel v0 {#vercel-v0}
 
-[Vercel v0](https://vercel.com/docs/v0/api) is an expert model for generating full-stack apps, with framework-aware completions optimized for modern stacks like Next.js and Vercel.
+[Vercel v0](https://v0.app/docs/api/model) is an expert model for generating full-stack apps, with framework-aware completions optimized for modern stacks like Next.js and Vercel.
 It supports text and image inputs and provides fast streaming responses.
 
 The v0 models are [OpenAI-compatible models](/#openai-api-compatible), but Vercel is listed as first-class provider in the panel's settings view.