Function use_click_outside 

pub fn use_click_outside(
    target_element_id: ReadSignal<String>,
    on_click_outside: EventHandler<()>,
)

Registers a document-level click listener and calls the handler when the click happens outside of the element with the provided id.

This is useful for dropdowns, popovers, and context menus that should close when focus moves away from their root element.