Function decline_plugin_view 

pub fn decline_plugin_view(
    mb_registry: &MultibufferRegistryHandle,
    events: Option<&Arc<EventBus>>,
    view: BufferId,
    message: &str,
)

Report a guest decline on an already-seated view.

The view stays open with the guest’s message in its headerline rather than vanishing: by the time build answers, the user is looking at the buffer, and closing it under them is worse than telling them why it is empty.