remove more email related code

api/backends.py

@@ -1,17 +0,0 @@
-from django.contrib.auth import get_user_model
-from django.contrib.auth.backends import ModelBackend
-
-
-class EmailBackend(ModelBackend):
-    def authenticate(self, request, username=None, password=None, **kwargs):
-        UserModel = get_user_model()
-        if not password:
-            return None
-        try:
-            user = UserModel.objects.get(email=username)
-        except UserModel.DoesNotExist:
-            return None
-        else:
-            if user.check_password(password):
-                return user
-        return None

api/models.py

@@ -75,6 +75,10 @@ class User(AbstractUser):
 
     objects = CustomUserManager()
 
+    # Log in with username + password only; email is optional and not prompted
+    # by createsuperuser.
+    REQUIRED_FIELDS = []
+
 
 class TemporaryUser(models.Model):
     t_id = models.AutoField(primary_key=True)

apibase/settings.py

@@ -157,9 +157,9 @@ DATABASES = {
 # Password validation
 # https://docs.djangoproject.com/en/5.0/ref/settings/#auth-password-validators
 
-# Uses email as username for login
+# Log in with username + password (default Django backend)
 AUTH_USER_MODEL = "api.User"
-AUTHENTICATION_BACKENDS = ["api.backends.EmailBackend"]
+AUTHENTICATION_BACKENDS = ["django.contrib.auth.backends.ModelBackend"]
 
 AUTH_PASSWORD_VALIDATORS = [
     {