OptionalautoFocus the input on mount — e.g. when the box appears from a collapsed toggle.
OptionalclassOptionalonWhen set, the clear (✕) button dismisses the whole box instead of just clearing the query: it resets the search and then calls this. Used by PdfToolbar to close its collapsed mobile search row. The button is then always shown (so the box can be closed before anything is typed).
OptionalplaceholderOptionalstyle
Props for PdfSearchBox.