Sidebar Navigation with Icons & Collapse

Create a full-height sidebar navigation component with:
- App logo at the top
- Navigation sections with headers (e.g. "Main", "Settings")
- 6 nav items each with a lucide-react icon and label
- Active item highlighted with background color
- One item with a collapsible submenu (3 sub-items)
- A collapse toggle button at the bottom that hides labels and shows only icons
- User avatar and name at the very bottom with a logout button
- Use shadcn/ui, Tailwind CSS, dark mode support