perf(demo): default Review passes to 1 for a faster try-it-out run
The review loop re-runs the reader/copy-editor each pass and is the dominant
cost; defaulting the demo to 1 pass roughly thirds the slowest phase. Users can
still raise it to 5.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>