No zero-width characters in docs / prose

Warn on zero-width Unicode runes (U+200B/U+200C/U+200D/U+FEFF) in documentation and prose files. These render invisibly, but:

• Word-count / readability tools mis-count
• Search / grep miss the highlighted word
• Diff renders fine but actual byte diff shows the smuggled rune

This is the docs-side companion to security/no-zero-width-in-source. WARN (not BLOCK) because some i18n libraries legitimately use ZWJ for Indic / Arabic shaping in user-facing strings.

Leading U+FEFF (BOM) at file position 0 is ignored - encoding/no-bom owns that case.

Fix#

Strip the offending characters:

LC_ALL=C sed -i 's/[\xE2\x80\x8B-\xE2\x80\x8D]//g' <file>

or in editors with “show invisible characters” turned on, delete by hand.

Deliberately not flagged#

• ZWJ between two emoji (👩‍💻) - the standard way to compose one glyph from two. A joiner between letters is still reported.