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/public/pwa-icon.svg

@@ -0,0 +1,15 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 64 64" fill="none">
+  <defs>
+    <linearGradient id="grad" x1="0" y1="0" x2="1" y2="1">
+      <stop offset="0%" stop-color="#38bdf8" />
+      <stop offset="100%" stop-color="#6366f1" />
+    </linearGradient>
+  </defs>
+  <rect width="64" height="64" rx="14" fill="#020617" />
+  <path
+    d="M16 40c0-8 6.5-14.5 14.5-14.5H36v-1.5c0-3.6-2.9-6.5-6.5-6.5S23 20.4 23 24h-7c0-7.5 6.1-13.5 13.5-13.5S43 16.5 43 24v6h2.5C50.4 30 55 34.6 55 40s-4.6 10-10.5 10H22.5C16.5 50 12 45.4 12 40Z"
+    fill="url(#grad)"
+  />
+  <circle cx="25" cy="39" r="4" fill="#f8fafc" />
+  <circle cx="41" cy="39" r="4" fill="#f8fafc" />
+</svg>