Function patch_seq_string_length 

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

Get the length of a string in Unicode characters (code points)

Stack effect: ( str – int )

Note: This returns character count, not byte count. For UTF-8 byte length (e.g., HTTP Content-Length), use string-byte-length.

Safety

Stack must have a String value on top