[tooltip][popover] Support inline positioning

# Feature request

## Summary
> When the anchor element is an inline element that spans over two lines, the positioner doesn't point to one of the `ClientRect`s.

Instead, we'd like to render the floating element "inline" with the text. Making it stick to the closest client rect.

## Relations
This issue mirrors the https://github.com/mui/base-ui/issues/2064

## Examples in other libraries

- https://base-ui.com/react/components/preview-card#PreviewCardPositioner-alignOffset
- https://floating-ui.com/docs/inline

No files or tests are named. Start by tracing the tooltip and popover positioning entry points, then compare the linked Base UI and Floating UI examples; done means an inline anchor spanning multiple lines positions the floating element against the closest client rect.

Written by the indexing model from the issue text.