- Replace top header with left sidebar navigation
- Sidebar shows module-aware nav items filtered by /api/modules
- Collapsible: expanded shows icon+label, collapsed shows icon only
- Toggle with Ctrl+J or collapse button, state persisted in localStorage
- Keyboard navigable: Arrow Up/Down, Enter to navigate, Escape to collapse
- Bottom section: density toggle, user info with role badge, logout
- Add useModules hook for fetching module state
- Add sidebar density variables to theme.css
Closes#113, closes#114
42a901f39c