pub fn declined(view_id: &str, message: String) -> ProviderViewOutcomeExpand description
Turn a guest decline into the generic outcome.
Separate function because the message is the GUEST’s — the host must not
reword it. build returning err means “there is nothing to show and here
is why”, which is a first-class outcome and not an error path: opening an
empty view and leaving the user to guess is the worse UX.