Keeps both the callout-parts test and main's ungroup tests in
automation.rs. Carries the shared fix for main's rules.rs build break
(content_streams now returns ContentStream; join via text::joined).
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Pq7HyCHD1R3rywQBPCHXZA