- Redesign ChangedFilesModal as a two-view navigation flow (file list → file detail) with back navigation
- Fix theming and loading/reading ergonomics for the diff viewer
- Enhance useChangedFiles hook with improved loading and error states
- Add comprehensive tests for modal navigation, diff rendering, and edge cases
- Update styles with mobile-friendly layout and diff viewer improvements
- Update dashboard README with mobile navigation description
- Add backend API endpoint to get changed files and diffs for a task worktree
- Add useChangedFiles hook for fetching and managing diff data
- Create ChangedFilesModal component with file list and diff viewer
- Integrate modal into TaskCard with click handler to view changes
- Add frontend API integration and type definitions
- Include unit tests for hook and modal components
- Add changeset for the new feature
- Remove deprecated mission-related test files
