feat: add profile setup, verification, and authentication context

- Implement ProfileSetup component for user profile creation with username validation.
- Create ProtectedRoute component to guard routes based on authentication status.
- Add VerifyAuthCode component for email verification with resend functionality.
- Establish AuthContext for managing user authentication state and actions.
- Enhance CookieContext for consent management with server-side verification.
- Set up Firebase configuration for authentication and analytics.
- Update styles for authentication components and header layout.
- Configure Vite proxy for API requests during development.

frontend/vite.config.ts

@@ -7,6 +7,12 @@ export default defineConfig({
   server: {
     hmr: {
       overlay: false
+    },
+    proxy: {
+      '/api': {
+        target: 'http://localhost:3000',
+        changeOrigin: true
+      }
     }
   }
 })