feat: add initial implementation of Kitchen CRM with authentication and dashboard features

- Create global styles and theme management
- Implement app shell layout with sidebar navigation
- Add authentication layout and pages for login and registration
- Develop dashboard page with placeholder content
- Introduce routing guards for guest-only and authenticated routes
- Set up Zustand for state management of authentication and theme
- Create API types and structures for CRM entities
- Configure Vite with PWA support and Tailwind CSS

frontend/src/components/ui/tooltip.tsx

@@ -0,0 +1,25 @@
+import * as React from 'react'
+import * as TooltipPrimitive from '@radix-ui/react-tooltip'
+
+import { cn } from '@/lib/utils'
+
+const TooltipProvider = TooltipPrimitive.Provider
+
+const Tooltip = TooltipPrimitive.Root
+
+const TooltipTrigger = TooltipPrimitive.Trigger
+
+const TooltipContent = React.forwardRef<
+  React.ElementRef<typeof TooltipPrimitive.Content>,
+  React.ComponentPropsWithoutRef<typeof TooltipPrimitive.Content>
+>(({ className, sideOffset = 4, ...props }, ref) => (
+  <TooltipPrimitive.Content
+    ref={ref}
+    sideOffset={sideOffset}
+    className={cn('z-50 overflow-hidden rounded-md border bg-popover px-3 py-1.5 text-xs text-popover-foreground shadow-md', className)}
+    {...props}
+  />
+))
+TooltipContent.displayName = TooltipPrimitive.Content.displayName
+
+export { Tooltip, TooltipContent, TooltipProvider, TooltipTrigger }