Bug: Remove React as required peer dependency

[onmax]

Prerequisites

• I have searched for duplicate or closed issues
• I have read the contributing guidelines

Describe the issue

I am integrating the vanilla FileTree API in Reka UI here: unovue/reka-ui#2700. The related Pierre Vue adapter PR is #652. I am also integrating the Diff primitives in Reka UI here: unovue/reka-ui#2701, related to the Pierre Vue Diff adapter PR: #653.

The packages expose non-React entrypoints, but they currently declare react and react-dom as non-optional peer dependencies, so Vue consumers still see/install React peers.

Would you prefer:

• marking React peers optional,
• moving React peers to the @pierre/trees/react entrypoint/package surface,
• or another recommended setup for vanilla consumers?

Motivation and context

This would make @pierre/trees and @pierre/diffs easier to adopt from Vue/Reka UI and downstream Nuxt UI

Reproduction

n/a

What browser(s) are you seeing the problem on?

No response

What version of @pierre/diffs are you using?

latest

[SlexAxton]

As long as optionalDeps works for the react folks, I'd be happy to take this PR to change to optional deps.