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/toaster.tsx

@@ -0,0 +1,24 @@
+import { Fragment } from 'react'
+
+import { Toast, ToastClose, ToastDescription, ToastProvider, ToastTitle, ToastViewport } from '@/components/ui/toast'
+import { useToast } from '@/components/ui/use-toast'
+
+export const Toaster = () => {
+  const { toasts, dismiss } = useToast()
+
+  return (
+    <ToastProvider swipeDirection="right">
+      <ToastViewport />
+      {toasts.map(({ id, title, description, action, ...toast }) => (
+        <Toast key={id} onOpenChange={(open) => !open && dismiss(id)} {...toast}>
+          <div className="grid gap-1">
+            {title ? <ToastTitle>{title}</ToastTitle> : null}
+            {description ? <ToastDescription>{description}</ToastDescription> : null}
+          </div>
+          {action ? <Fragment>{action}</Fragment> : null}
+          <ToastClose />
+        </Toast>
+      ))}
+    </ToastProvider>
+  )
+}