Function patch_seq_base64url_encode 

#[unsafe(no_mangle)]
pub unsafe extern "C" fn patch_seq_base64url_encode(
    stack: Stack,
) -> Stack

Encode a string to URL-safe Base64 (no padding)

Stack effect: ( String – String )

Uses URL-safe alphabet (- and _ instead of + and /) with no padding. Suitable for JWTs, URLs, and filenames.

Safety

Stack must have a String value on top