- Add viewport-gated fetching to TaskCard component so only visible cards load their data
- Implement lightweight memo comparison to prevent unnecessary re-renders
- Add lazy enable gates to useSessionFiles and useTaskDiffStats hooks with caching
- Add comprehensive tests for useSessionFiles and useTaskDiffStats hooks
- Document viewport-gated loading patterns in memory and dashboard-load performance docs
- Create useTaskDiffStats hook to extract and compute diff stats from task data
- Use hook in TaskCard component for consistent done file count display
- Add diffStats priority tests ensuring diff stats take precedence over steps
- Add useTaskDiffStats mock and comprehensive unit tests for the hook
