refactor(member-live): modularize the overview and drop the superseded in-memory paths

Extract the cookie parser, export-payload builder and fee-status helper
into their own modules and remove the filter/sort/load helpers the
database pushdown made dead, so the overview LiveView stays a thin
coordinator over focused units.

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

@@ -21,6 +21,8 @@ defmodule MvWeb.MemberLive.Index.ViewSettings do
   cookie is read directly from the request conn.
   """
 
+  alias MvWeb.MemberLive.Index.Cookie
+
   @cookie_name "member_view_settings"
   @session_key "member_view_settings"
   @connect_param "view_settings"
@@ -117,7 +119,7 @@ defmodule MvWeb.MemberLive.Index.ViewSettings do
     case Plug.Conn.get_req_header(conn, "cookie") do
       [cookie_header | _rest] ->
         cookie_header
-        |> parse_cookie_header()
+        |> Cookie.parse_header()
         |> Map.get(@cookie_name)
         |> parse_json()
 
@@ -170,17 +172,4 @@ defmodule MvWeb.MemberLive.Index.ViewSettings do
   end
 
   defp parse_json(_), do: %{}
-
-  # Parses a cookie header string into a name => value map.
-  defp parse_cookie_header(cookie_header) when is_binary(cookie_header) do
-    cookie_header
-    |> String.split(";")
-    |> Enum.map(&String.trim/1)
-    |> Enum.map(&String.split(&1, "=", parts: 2))
-    |> Enum.reduce(%{}, fn
-      [key, value], acc -> Map.put(acc, key, URI.decode(value))
-      [key], acc -> Map.put(acc, key, "")
-      _, acc -> acc
-    end)
-  end
 end