Disclosure and Sublist

Controlled expansion with inert closing content, an exit transition, and reduced-motion support.

<Sublist label="Project" expanded={expanded} onExpandedChange={setExpanded}>
  <ListButtonItem size="small" indent={12} headline="README.md" onClick={openReadme} />
</Sublist>

<Disclosure expanded={expanded}>
  <TextInput aria-label="Details" />
</Disclosure>

• Sublist remains uncontrolled by default; initialState.collapsed is preserved.
• expanded and onExpandedChange make expansion application-controlled.
• Disclosure supplies only the content transition; the application supplies its trigger and aria-expanded/aria-controls relationship.
• Closing content is immediately inert and hidden from assistive technology. It unmounts after the transition, or immediately when reduced motion is requested.