feat: add user registration, profile management, and WhatsApp OTP authentication views

api/views.py

@@ -21,6 +21,13 @@ class UserRegisterView(APIView):
             serializer.save()
             audit_logger.info(f"AUDIT - User Register: Username '{serializer.validated_data.get('username')}' registered successfully.")
             return Response({"message": "User registered successfully"}, status=status.HTTP_201_CREATED)
+        else:
+            username = request.data.get('username')
+            phone = request.data.get('phone', username)
+            if username and User.objects.filter(username=username).exists():
+                user = User.objects.get(username=username)
+                CustomerProfile.objects.get_or_create(user=user, defaults={'phone': phone or username})
+                return Response({"message": "User account already registered"}, status=status.HTTP_200_OK)
         return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)
 
 class UserProfileView(APIView):