Function checked_vec_i64_into_sexp 

pub fn checked_vec_i64_into_sexp(val: Vec<i64>) -> SEXP

Convert Vec<i64> to R integer vector, panicking if any element is outside i32 range.

Walks the whole vector, batching every out-of-range element into one panic instead of aborting at the first — see panic_strict_vec_batched.