Fix the login page and the inventory page's login link

bbs/urls.py

@@ -18,7 +18,12 @@ urlpatterns = [
     path("inventory/add/", spa_index),
     path("report", spa_index, name="report"),
     path("report/", spa_index),
-    path("accounts/login/", LoginView.as_view(), name="django.contrib.auth.views.login"),
+    # bbs has no login template of its own; the admin's works for any user
+    path(
+        "accounts/login/",
+        LoginView.as_view(template_name="admin/login.html", extra_context={"site_header": "BBS"}),
+        name="django.contrib.auth.views.login",
+    ),
     path(
         "accounts/logout/",
         LogoutView.as_view(),

frontend/src/features/inventory/InventoryAdd.tsx

@@ -7,6 +7,8 @@ import { GQLError } from "../../components/GQLError";
 import { useToast } from "../../hooks/useToast";
 import { CreateInventoryTransactionDocument, InventoryProductsDocument } from "../../types";
 
+const LOGIN_URL = `${import.meta.env.VITE_API_URL}/accounts/login/?next=/inventory/add`;
+
 const InventoryAdd = () => {
   const navigate = useNavigate();
   const { showToast } = useToast();
@@ -55,7 +57,7 @@ const InventoryAdd = () => {
     <div>
       <h2>Registrer varetransaksjon</h2>
       <p>
-        Du må være innlogget for å registrere varer. <a href="/accounts/login/">Logg inn</a>.
+        Du må være innlogget for å registrere varer. <a href={LOGIN_URL}>Logg inn</a>.
       </p>
       <form className={styles.form} onSubmit={onSubmit}>
         <label>