fix: Use CustomUserAdmin instead of Django's default UserAdmin to fix user creation bug

The bug was caused by importing Django's default UserAdmin instead of
CustomUserAdmin in admin.py. This bypassed all custom admin logic.

Additionally, CustomUserAdmin was modifying fieldsets without explicitly
preserving add_fieldsets, which can cause Django to not properly handle
the user creation form, leading to password hashing issues.

Changes:
- Updated admin.py to import and register CustomUserAdmin
- Explicitly set add_fieldsets in CustomUserAdmin to preserve Django's
  default user creation behavior and ensure passwords are properly hashed
- Added explanatory comments

Fixes #1707

Co-authored-by: Nick Sweeting <pirate@users.noreply.github.com>

archivebox/core/admin.py

@@ -7,11 +7,11 @@ from archivebox.core.models import Snapshot, ArchiveResult, Tag
 from archivebox.core.admin_tags import TagAdmin
 from archivebox.core.admin_snapshots import SnapshotAdmin
 from archivebox.core.admin_archiveresults import ArchiveResultAdmin
-from archivebox.core.admin_users import UserAdmin
+from archivebox.core.admin_users import CustomUserAdmin
 
 
 def register_admin(admin_site):
-    admin_site.register(get_user_model(), UserAdmin)
+    admin_site.register(get_user_model(), CustomUserAdmin)
     admin_site.register(ArchiveResult, ArchiveResultAdmin)
     admin_site.register(Snapshot, SnapshotAdmin)
     admin_site.register(Tag, TagAdmin)

archivebox/core/admin_users.py

@@ -10,6 +10,12 @@ class CustomUserAdmin(UserAdmin):
     sort_fields = ['id', 'email', 'username', 'is_superuser', 'last_login', 'date_joined']
     list_display = ['username', 'id', 'email', 'is_superuser', 'last_login', 'date_joined']
     readonly_fields = ('snapshot_set', 'archiveresult_set', 'tag_set', 'apitoken_set', 'outboundwebhook_set')
+
+    # Preserve Django's default user creation form and fieldsets
+    # This ensures passwords are properly hashed and permissions are set correctly
+    add_fieldsets = UserAdmin.add_fieldsets
+
+    # Extend fieldsets for change form only (not user creation)
     fieldsets = [*UserAdmin.fieldsets, ('Data', {'fields': readonly_fields})]
 
     @admin.display(description='Snapshots')