merge: resolve conflicts with main (keep autoresearch-clean versions)

PR #204 was merged to main while this branch was being developed.
All conflicts resolved in favor of the clean rework versions (ours):
- SKILL.md: review/export approach over cherry-pick
- optimization-guide.md: snapshot review terminology
- eval_viewer.html: radio selection, setActivePage helper, optimization-only mode
- eval_compare.py: standalone is_optimization_data() validator

Author: notque