Add lazy-mount options where appropriate.

[kotAPI]

Description

Add lazy-mount options where appropriate for components that render non-visible content eagerly.

This should be limited to components where deferred mounting can reduce initial render cost without breaking expected behavior, accessibility, or composition patterns.

Examples

Potential candidates:

• Tabs.Content
  Only mount the active panel instead of rendering every panel up front when there are many tabs or heavy panel contents.

• Accordion.Content
  Delay mounting collapsed content until a section is opened, especially when panels contain expensive trees.

• Dialog, Popover, or DropdownMenu content
  Avoid mounting overlay content before the overlay is opened if that content is not needed for initial render.

• Tooltip / HoverCard
  Defer rendering floating content until interaction happens instead of mounting all hidden overlays eagerly.

• large composed lists inside overlays
  If a menu or popover contains a heavy subtree, lazy mounting can avoid paying that cost before the user opens it.

Acceptance Criteria

1. Appropriate components are reviewed for lazy-mount support.
2. Lazy-mount options are added only where behavior remains predictable and accessible.
3. Tests cover mount/unmount behavior and any affected lifecycle expectations.
4. Docs/storybook are updated for any new API or behavior.
5. Add a changeset only if there is user-facing impact.