fix: implement review comments

lib/mv_web/live/member_live/index.ex

@@ -977,6 +977,7 @@ defmodule MvWeb.MemberLive.Index do
     end
   end
 
+  # Multiple group filters combine with AND: member must match all selected group conditions.
   defp apply_group_filters(query, group_filters, _groups) when group_filters == %{}, do: query
 
   defp apply_group_filters(query, group_filters, groups) do
@@ -1103,9 +1104,10 @@ defmodule MvWeb.MemberLive.Index do
   end
 
   defp valid_sort_field_db_or_custom?(field) when is_binary(field) do
-    field == "groups" or
-      custom_field_sort?(field) or
-      ((atom = safe_member_field_atom_only(field)) != nil and valid_sort_field_db_or_custom?(atom))
+    normalized = if field == "groups", do: :groups, else: safe_member_field_atom_only(field)
+
+    (normalized != nil and valid_sort_field_db_or_custom?(normalized)) or
+      custom_field_sort?(field)
   end
 
   defp safe_member_field_atom_only(str) do
@@ -1161,11 +1163,11 @@ defmodule MvWeb.MemberLive.Index do
   end
 
   defp sort_members_by_groups(members, order) do
-    # Members with groups first, then by first group name alphabetically
+    # Members with groups first, then by first group name alphabetically (min = first by sort order)
     first_group_name = fn member ->
-      groups = member.groups || []
-      names = Enum.map(groups, & &1.name) |> Enum.sort()
-      List.first(names)
+      (member.groups || [])
+      |> Enum.map(& &1.name)
+      |> Enum.min(fn -> nil end)
     end
 
     members