- Add API client functions for commit history and detail endpoints
- Create GitHistoryPage with commit list, graph visualization, and detail panel
- Add branch selector for viewing different branches
- Integrate history view into repository list with History button
- Add comprehensive CSS styles for history page layout
Quality gates: typecheck ✓, lint ✓, build ✓
- Add theme support with dark/light/system modes
- Add useTheme hook for applying user config theme
- Update router to use SettingsPage
- Update app-shell to apply theme on load
- Add CSS variables for dark theme
- Fix mypy errors in user_config.py
- Quality gates pass: ruff, mypy, typecheck, lint, build