Add before/after gifs demonstrating the interactive add cast automation

Recorded with asciinema + agg for the PR description: before.gif shows
the previous helper stalling on the wizard's first prompt (waiting on a
human keystroke that a scripted recording never provides), after.gif
shows the current pty-driven helper completing the whole wizard
unattended. Not meant as permanent documentation assets.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_018L8LELgMvNRvxVPWGGhzFC

Author: claude