- Version dropdown appears when version_count > 0 (hidden until first re-run)
- Selecting a historical version overlays snapshot content (title, summary, body, chains, plugins)
- Key moments and related links always show live data (not versioned)
- Pipeline metadata block shows model, capture time, and prompt file hashes (truncated)
- Cyan banner when viewing historical version with "Back to current" button
- fetchTechniqueVersion API function for single version detail