Zero-width character remover

The table covers zero width space, joiners, word joiner, the invisible math operators, byte order mark, soft hyphen, and the U+E0000 tag block. It does not cover look-alike homoglyph letters or the U+202A bidi controls, which are a reordering trick rather than hidden payload; the Unicode inspector lists those per character. Two honest costs: the zero width joiner holds emoji sequences together, and the non-joiner keeps some scripts from running their letters together, so a finding there can mean the cleanup changes how text renders, not just how it hides.