Docs: Document <Button> Props

[ericdellacasa8]

Context

The README lists the available Elements components, but individual component props are not yet documented in detail.

<Button> is one of the most commonly used components, so it is a good first component to document clearly.

Definition of Done

Add documentation for the <Button> component props.

The documentation should:

• Include a props table for <Button>
• Cover common props such as text, children, href, backgroundColor, color, fontSize, fontFamily, padding, borderRadius, and textAlign
• Document nested escape hatches such as buttonColors and border
• Note that fontFamily must be { label, value }, not a string
• Note that fontWeight must be a number
• Include default values where available
• Be added to packages/react/README.md, Storybook autodocs, or another appropriate docs location

Example Outcome

A developer evaluating or using Elements should be able to quickly understand which props <Button> accepts and how to use them correctly.

For example, the documentation should make it clear that:

<Button
  href="https://example.com"
  backgroundColor="#000000"
  color="#ffffff"
  borderRadius="8px"
>
  Get started
</Button>

is valid usage, while also documenting the more advanced prop shapes where needed.

Where to Start

Useful references already exist in the codebase:

• packages/react/src/components/Button.tsx
• Button.stories.tsx
• packages/shared/src/utils/semantic-props.ts

The goal is to turn the existing component props and examples into clear public documentation.