## Problem
We want to upgrade to react 19. However some libraries aren't compatible
with it. Besides, `next-mdx-remote` is now archived and not maintained
anymore.
## Solution
The [NextJS
documentation)[https://nextjs.org/docs/15/app/guides/mdx#remote-mdx]
suggest using
[`next-mdx-remote-client`](https://github.com/ipikuka/next-mdx-remote-client)
which was a fork of `next-mdx-remote`.
- [x] migrate `apps/www` from `next-mdx-remote` to
`next-mdx-remote-client`
- [x] migrate `apps/www` from `next-mdx-remote` to
`next-mdx-remote-client`
I haven't noticed any change in the pages.
When upgrading to react 19, we'll have to use v2 of
`next-mdx-remote-client`.
<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit
* **Refactor**
* Switched MDX rendering/serialization to a newer client-focused
implementation across docs and site for improved compatibility.
* **Bug Fixes**
* Improved handling of serialization errors so MDX failures render clear
fallback messages instead of breaking pages.
* **Chores**
* Updated local environment template value for the public anonymous key.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->