Function is_display_separator 

pub fn is_display_separator(c: char) -> bool

True for any character treated as a display separator on intake: ALL Unicode whitespace plus - and ,. SPEC §3.2 (mstring display-grouping). None of these appear in the codex32 alphabet (qpzry9x8gf2tvdw0s3jn54khce6mua7l) or the ms/mk/md/1 structural chars (SPEC §4), so stripping is unambiguous.