- Add theme-aware CSS classes for changed-file status badges (added, modified, deleted, renamed)
- Update ChangedFilesModal, CommitDiffTab, and TaskChangesTab to use theme-aware status classes
- Add comprehensive tests for ChangedFilesModal and TaskChangesTab status styling
- Refactor stuck-task-detector to extract StuckTaskConfig and simplify detection logic
- Clean up 370+ lines of redundant test code in stuck-task-detector tests
- Update dashboard README with theme-aware styling notes
- Pass throughChangedFiles option in executor for better diff handling
- Refactor TaskChangesTab to use merge commit diff for done/archived tasks instead of branch diff
- Add CommitDiffTab component integration for displaying merge commit changes
- Remove legacy API endpoints and tests for branch-based diff on completed tasks
- Add comprehensive test suite for TaskChangesTab covering all task lifecycle states
- Document merge commit diff behavior in dashboard README
