Function coerce_widened 

fn coerce_widened(check: RTypeCheck, ty: &Type) -> RTypeCheck

Keep the R gate in sync with the conversion actually selected for this type.

Native i32 widens to whole-number doubles (plus logical/raw), so its gate becomes the lossless whole-number predicate; Vec<i32> moves from the INTSXP-only gate (#616) to the same wide predicate the other integer vectors use. Native f64 / Vec<f64> move from the is.double gate to the loose numeric predicate. Option<bool> has no coercion mapping and stays nullable logical.