tr/sed lowercase differently from str.lower() outside ASCII, so a name
like "İstanbul-creator-claude" was started as x--stanbul-... while the
row's attach_command named i-stanbul-.... A non-ASCII name is now
lowercased and replaced by python3 (fail closed without it), and the
name is read with printf, not echo ("-n" no longer vanishes).
Refs #71
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>