feat(member): condense the overview into composite name and address cells

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

@@ -29,7 +29,28 @@ defmodule MvWeb.MemberLive.Index.FieldVisibility do
 
   # Single UI key for "Membership Fee Status"; only this appears in the dropdown.
   # Groups and membership_fee_type are also pseudo fields (not in member_fields(), displayed in the table).
-  @pseudo_member_fields [:membership_fee_status, :membership_fee_type, :groups]
+  # :name and :address are composite display-only columns (Name = name + email,
+  # Address = street/house number over postal code/city).
+  @pseudo_member_fields [:membership_fee_status, :membership_fee_type, :groups, :name, :address]
+
+  # Curated default-visible column set (§1.2): the columns shown on first visit
+  # when there is no persisted selection and no global override. Everything else
+  # (the individual name/address sub-fields, notes, dates other than join date)
+  # defaults to hidden so the table fits common desktop widths.
+  @default_visible_fields MapSet.new([
+                            :name,
+                            :address,
+                            :membership_fee_type,
+                            :membership_fee_status,
+                            :groups,
+                            :join_date
+                          ])
+
+  @doc """
+  The curated default-visible columns (member-field atoms) for a first visit.
+  """
+  @spec default_visible_fields() :: [atom()]
+  def default_visible_fields, do: MapSet.to_list(@default_visible_fields)
 
   # Export/API may accept this as alias; must not appear in the UI options list.
   @export_only_alias :payment_status
@@ -276,13 +297,13 @@ defmodule MvWeb.MemberLive.Index.FieldVisibility do
     domain_map =
       Enum.reduce(domain_fields, %{}, fn field, acc ->
         field_string = Atom.to_string(field)
-        default_visibility = if field == :exit_date, do: false, else: true
+        default_visibility = MapSet.member?(@default_visible_fields, field)
         show_in_overview = Map.get(visibility_config, field, default_visibility)
         Map.put(acc, field_string, show_in_overview)
       end)
 
     Enum.reduce(@pseudo_member_fields, domain_map, fn field, acc ->
-      Map.put(acc, Atom.to_string(field), true)
+      Map.put(acc, Atom.to_string(field), MapSet.member?(@default_visible_fields, field))
     end)
   end