- Created comprehensive FEATURE_PLAN-reordering.md with 9 tasks in 3 phases
- Must-Have: Touch-Support for mobile drag-and-drop
- Admin-only: Reordering restricted to ModerationGroupImagesPage
- Public users cannot reorder images (security restriction)
- Technical approach: @dnd-kit/core + PUT /api/groups/:groupId/reorder
- Estimated: 10-12 hours over 2-3 days
