feat: keep empty cells consistent empty

test/mv_web/member_live/index_groups_display_test.exs

@@ -95,6 +95,20 @@ defmodule MvWeb.MemberLive.IndexGroupsDisplayTest do
     assert html =~ member3.first_name
   end
 
+  test "empty group cell is visually empty with sr-only text (no dash)", %{
+    conn: conn,
+    member3: member3
+  } do
+    conn = conn_with_oidc_user(conn)
+    {:ok, _view, html} = live(conn, "/members")
+    assert html =~ member3.first_name
+    # Screen reader gets a meaningful label for the empty cell
+    assert html =~ "sr-only"
+    assert html =~ "No group assignment"
+    # No visible dash as placeholder (Design Guidelines §8.6)
+    refute html =~ ~r/<span[^>]*class="[^"]*text-base-content\/50[^"]*"[^>]*>—<\/span>/
+  end
+
   test "displays group name correctly in badge", %{conn: conn, group1: group1} do
     conn = conn_with_oidc_user(conn)
     {:ok, _view, html} = live(conn, "/members")