Add backlogger app at /backlogger/ with login protection

Django app with Item model (games/books/films/other categories), CRUD
views, and login-required access. Login page at /accounts/login/ uses
custom dark-themed template consistent with the site design.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backlogger/urls.py

@@ -0,0 +1,10 @@
+from django.urls import path
+from . import views
+
+app_name = 'backlogger'
+urlpatterns = [
+    path('', views.item_list, name='list'),
+    path('add/', views.item_add, name='add'),
+    path('<int:pk>/edit/', views.item_edit, name='edit'),
+    path('<int:pk>/delete/', views.item_delete, name='delete'),
+]