feat(member-live): sort the composite Member column by first or last name

lib/mv_web/live/member_live/index.ex

@@ -172,7 +172,7 @@ defmodule MvWeb.MemberLive.Index do
       socket
       |> Layouts.assign_page_title(gettext("Members"))
       |> assign(:query, "")
-      |> assign_new(:sort_field, fn -> :first_name end)
+      |> assign_new(:sort_field, fn -> :last_name end)
       |> assign_new(:sort_order, fn -> :asc end)
       |> assign(:cycle_status_filter, nil)
       |> assign(:group_filters, %{})
@@ -379,6 +379,22 @@ defmodule MvWeb.MemberLive.Index do
       end
 
     {new_field, new_order} = determine_new_sort(field, socket)
+    {:noreply, apply_sort_change(socket, new_field, new_order)}
+  end
+
+  # The composite "Member" column's sub-field menu (first name / last name) always
+  # sorts ascending by the chosen field: it switches the sort key rather than
+  # toggling direction (a click on the header itself toggles direction).
+  def handle_event("sort_composite", %{"field" => field_str}, socket) do
+    field = String.to_existing_atom(field_str)
+    {:noreply, apply_sort_change(socket, field, :asc)}
+  end
+
+  # Applies a resolved (field, order) sort: updates assigns and the sort-header
+  # components, reloads the keyset stream from page 1, scrolls to top, and syncs
+  # the URL. Shared by the header-click ("sort") and sub-field menu
+  # ("sort_composite") paths.
+  defp apply_sort_change(socket, new_field, new_order) do
     old_field = socket.assigns.sort_field
 
     socket =
@@ -394,8 +410,8 @@ defmodule MvWeb.MemberLive.Index do
     query_params =
       build_query_params(
         opts_for_query_params(socket, %{
-          sort_field: ExportPayload.sort_field(socket.assigns.sort_field),
-          sort_order: ExportPayload.sort_order(socket.assigns.sort_order)
+          sort_field: ExportPayload.sort_field(new_field),
+          sort_order: ExportPayload.sort_order(new_order)
         })
       )
       |> maybe_add_field_selection(
@@ -403,7 +419,7 @@ defmodule MvWeb.MemberLive.Index do
         socket.assigns[:fields_in_url?] || false
       )
 
-    {:noreply, push_reload(socket, ~p"/members?#{query_params}")}
+    push_reload(socket, ~p"/members?#{query_params}")
   end
 
   # -----------------------------------------------------------------
@@ -1488,9 +1504,11 @@ defmodule MvWeb.MemberLive.Index do
   defp determine_field(default, nil), do: default
 
   # Computed/pseudo fields that are nonetheless sortable (they resolve to DB
-  # sort keys in OverviewQuery): groups aggregate and the composite Name/Address
-  # columns. Other computed fields (e.g. membership_fee_status) are not sortable.
-  @sortable_computed_fields [:groups, :name, :address]
+  # sort keys in OverviewQuery): the groups aggregate and the composite Address
+  # column. The composite Member column sorts by its real first/last-name
+  # sub-fields (chosen via its sub-field menu), so it needs no pseudo token here.
+  # Other computed fields (e.g. membership_fee_status) are not sortable.
+  @sortable_computed_fields [:groups, :address]
 
   defp determine_field(default, sf) when is_binary(sf) do
     sortable_strings = Enum.map(@sortable_computed_fields, &Atom.to_string/1)

lib/mv_web/live/member_live/index.html.heex

@@ -170,17 +170,12 @@
       <:col
         :let={member}
         :if={:name in @member_fields_visible and @compact_member}
-        sort_field={:name}
+        sort_field={if @sort_field in [:first_name, :last_name], do: @sort_field}
         label={
           ~H"""
-          <.live_component
-            module={MvWeb.Components.SortHeaderComponent}
-            id={:sort_name}
-            field={:name}
-            label={gettext("Name")}
+          <MvWeb.Components.MemberNameSortHeader.composite_name_sort_header
             sort_field={@sort_field}
             sort_order={@sort_order}
-            sort_hint={gettext("Click to sort by last name")}
           />
           """
         }

lib/mv_web/live/member_live/index/overview_query.ex

@@ -254,12 +254,19 @@ defmodule MvWeb.MemberLive.Index.OverviewQuery do
   defp apply_sort(query, nil, _order, _custom_fields), do: Ash.Query.sort(query, id: :asc)
   defp apply_sort(query, _field, nil, _custom_fields), do: Ash.Query.sort(query, id: :asc)
 
-  # Composite "Member" column: sort by last name then first name. The email that
-  # shares the cell is display-only and does not affect the sort key (§1.21).
-  defp apply_sort(query, field, order, _custom_fields) when field in [:name, "name"] do
+  # Composite "Member" column sub-fields (§1.21). Sorting by one name part uses
+  # the other name part (then id) as a stable tie-breaker; the email that shares
+  # the cell is display-only and never a sort key. Shared by the composite
+  # sub-field menu and the separate first/last-name columns.
+  defp apply_sort(query, field, order, _custom_fields) when field in [:last_name, "last_name"] do
     Ash.Query.sort(query, [{:last_name, order}, {:first_name, order}, {:id, :asc}])
   end
 
+  defp apply_sort(query, field, order, _custom_fields)
+       when field in [:first_name, "first_name"] do
+    Ash.Query.sort(query, [{:first_name, order}, {:last_name, order}, {:id, :asc}])
+  end
+
   # Composite "Address" column: sort by city, then postal code, then street.
   defp apply_sort(query, field, order, _custom_fields) when field in [:address, "address"] do
     Ash.Query.sort(query, [