feat(auth): implement multi-step authentication flow with UI

This commit replaces the placeholder login page with a comprehensive, multi-step authentication system. It introduces a new `AuthPage` that orchestrates the user flow between login, signup, and OTP verification.

- **Login Form**: Supports both email and WhatsApp credentials, with input validation and API integration.
- **Signup Form**: Includes fields for full name, email, and WhatsApp, with real-time password strength validation.
- **OTP Form**: Provides a view for users to verify their account after signup.
- **UI/UX**: The entire authentication experience is restyled with a new background, Poppins font, custom brand colors, and improved form components for a polished look and feel.
- **Dependencies**: Adds `axios` for handling API requests to the backend.

BREAKING CHANGE: The `LoginPage` component has been deleted and is replaced by the new `AuthPage` component. All references to `LoginPage` must be updated.

adventure-rental-app/src/index.css

@@ -1,3 +1,19 @@
 @tailwind base;
 @tailwind components;
 @tailwind utilities;
+
+body {
+  @apply bg-login-bg bg-cover bg-center font-sans;
+}
+
+/* Webkit Autofill Override */
+input:-webkit-autofill,
+input:-webkit-autofill:hover,
+input:-webkit-autofill:focus,
+input:-webkit-autofill:active {
+  -webkit-text-fill-color: #fff !important;
+  background-color: transparent !important;
+  -webkit-box-shadow: 0 0 0px 1000px rgba(0, 0, 0, 0.10) inset !important;
+  transition: background-color 5000s ease-in-out 0s;
+}
+