Compose for wasm never focuses the semantics node carrying the testTag.
It proxies keystrokes through a hidden 1px backing input that is a
sibling of the a11y tree, so the node the runner tapped never held focus
and confirmFocus refused to type into every Compose text field.
Focus is re-attributed to the smallest editable whose box holds the
caret's centre. Centre-point rather than full containment because the
caret's height comes from the text style and the field's from its layout
box, so a taller font would silently drop back to refusing.
