- add lucide-react for Sun/Moon icons - add useTheme hook persisting choice to localStorage with prefers-color-scheme fallback - add ThemeSwitcher button component wired into SidePanel header - add blocking inline script to index.html to prevent flash-of-wrong-theme - move all *.stories.tsx from src/ into .storybook/stories/ and update imports - update main.ts stories glob to .storybook/stories/**