feat(auth): implement multi-step authentication flow

This commit introduces a complete user authentication system, replacing the previous placeholder login page. The new flow includes signup, login, and OTP verification, all integrated with backend webhooks.

- Adds `AuthPage` to manage the view state between login, signup, and OTP forms.
- Implements `LoginForm` with support for both email and WhatsApp credentials.
- Implements `SignupForm` with password strength and confirmation validation.
- Adds `OtpForm` for two-factor verification after a successful signup.
- Integrates `axios` for making API calls to the backend webhooks.
- Updates styling with a new background, custom brand colors, and the Poppins font.

BREAKING CHANGE: The `LoginPage` component has been deleted and is replaced by the new `AuthPage` component. Any imports of `LoginPage` must be updated.

adventure-rental-app/tailwind.config.js

@@ -17,7 +17,7 @@ export default {
         sans: ['Poppins', 'sans-serif'],
       },
       backgroundImage: {
-        'login-bg': "url('https://images.unsplash.com/photo-1515444744559-7be63e1600de?q=80&w=1170&auto=format&fit=crop&ixlib=rb-4.1.0&ixid=M3wxMjA3fDB8MHxwaG90by1wYWdlfHx8fGVufDB8fHx8fA%3D%3D')",
+        'login-bg': "url('https://images.unsplash.com/photo-1723067950251-af96d68b9c1e?q=80&w=1170&auto=format&fit=crop&ixlib=rb-4.1.0&ixid=M3wxMjA3fDB8MHxwaG90by1wYWdlfHx8fGVufDB8fHx8fA%3D%3D')",
       }
     },
   },