Piping a password into ssh -tt's pty raced and hung on the real run (worked in
a fast test, blocked for 14 min in practice). Replace with a temp
/etc/sudoers.d/mac-setup installed by _install_sudoers.sh (validated
before activation), removed on every exit path plus a 40-min on-Mac
self-destruct. setup.sh now fails fast if passwordless sudo is absent
instead of depending on a primed tty ticket.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>