feat(react-lang): support custom host wrappers for React Native

[greatjourney589]

What

Closes #523
Add support for custom host wrappers in @openui/react-lang's Renderer so it can render on non-web hosts like React Native / Expo.

Today the Renderer hardcodes <div> for its outer and inner wrappers and always falls back to a DOM spinner. On React Native, lowercase host tags like "div" are not valid components and crash with "View config getter callback for component div ...". This change lets callers supply native host components (e.g. View from react-native) instead.

Changes

• Add containerComponent and contentComponent props to RendererProps (default to "div"), so the outer/inner wrappers can be swapped for native hosts.
• Apply the web-only CSS opacity fade transition only when the content wrapper is a web host (string tag); skip it for native components to avoid warnings/crashes.
• Fall back to the default DOM spinner only on web hosts; on native, render nothing unless the caller passes their own queryLoader.
• Add react-dom + @types/react-dom as devDependencies and a vitest.config.ts to support component tests.
• Add Renderer tests covering default web div wrappers, custom native wrappers, transition omission on native, and null-response rendering.
• Update packages/react-lang/README.md with React Native usage docs.

Test Plan

Describe how you validated this change.

• Not applicable (explain why)
• Verified locally — vitest run in packages/react-lang passes (4/4 tests), covering web defaults, native wrappers, web-only transition handling, and null responses.

Checklist

• I linked a related issue, if applicable
• I updated docs/README when needed
• I considered backwards compatibility — new props are optional and default to "div", so existing web usage is unchanged.

[greatjourney589]

Hi, @vishxrad
I am very interested in your repository.This is my first PR.
When you have a moment, could you please review this PR?