refactor(import): drop unreachable CSV error-formatting path

consume_and_read_csv/2 and MemberCSV.prepare/2 only ever return {:error, binary()}, so the non-binary error branch and the format_error_message/* helpers it called were unreachable. Removed them and bound the remaining discarded locale/dispatch results.

lib/mv_web/live/import_live.ex

@@ -47,14 +47,11 @@ defmodule MvWeb.ImportLive do
   # after this limit is reached.
   @max_errors 50
 
-  # Maximum length for error messages before truncation
-  @max_error_message_length 200
-
   @impl true
   def mount(_params, session, socket) do
     # Get locale from session for translations
     locale = session["locale"] || "de"
-    Gettext.put_locale(MvWeb.Gettext, locale)
+    _ = Gettext.put_locale(MvWeb.Gettext, locale)
 
     # Get club name from settings
     club_name =
@@ -193,16 +190,6 @@ defmodule MvWeb.ImportLive do
            :error,
            gettext("Failed to prepare CSV import: %{reason}", reason: reason)
          )}
-
-      {:error, error} ->
-        error_message = format_error_message(error)
-
-        {:noreply,
-         put_flash(
-           socket,
-           :error,
-           gettext("Failed to prepare CSV import: %{reason}", reason: error_message)
-         )}
     end
   end
 
@@ -223,64 +210,6 @@ defmodule MvWeb.ImportLive do
     {:noreply, socket}
   end
 
-  # Formats error messages for user-friendly display.
-  #
-  # Handles various error types including Ash errors, maps with message fields,
-  # lists of errors, and fallback formatting for unknown types.
-  @spec format_error_message(any()) :: String.t()
-  defp format_error_message(error) do
-    case error do
-      %Ash.Error.Invalid{} = ash_error ->
-        format_ash_error(ash_error)
-
-      %{message: msg} when is_binary(msg) ->
-        msg
-
-      %{errors: errors} when is_list(errors) ->
-        format_error_list(errors)
-
-      reason when is_binary(reason) ->
-        reason
-
-      other ->
-        format_unknown_error(other)
-    end
-  end
-
-  # Formats Ash validation errors for display
-  defp format_ash_error(%Ash.Error.Invalid{errors: errors}) when is_list(errors) do
-    Enum.map_join(errors, ", ", &format_single_error/1)
-  end
-
-  defp format_ash_error(error) do
-    format_unknown_error(error)
-  end
-
-  # Formats a list of errors into a readable string
-  defp format_error_list(errors) do
-    Enum.map_join(errors, ", ", &format_single_error/1)
-  end
-
-  # Formats a single error item
-  defp format_single_error(error) when is_map(error) do
-    Map.get(error, :message) || Map.get(error, :field) || inspect(error, limit: :infinity)
-  end
-
-  defp format_single_error(error) do
-    to_string(error)
-  end
-
-  # Formats unknown error types with truncation for very long messages
-  defp format_unknown_error(other) do
-    error_str = inspect(other, limit: :infinity, pretty: true)
-
-    if String.length(error_str) > @max_error_message_length do
-      String.slice(error_str, 0, @max_error_message_length - 3) <> "..."
-    else
-      error_str
-    end
-  end
-
   @impl true
   def handle_info({:process_chunk, idx}, socket) do
     case socket.assigns do
@@ -337,32 +266,33 @@ defmodule MvWeb.ImportLive do
       actor: actor
     ]
 
-    if Config.sql_sandbox?() do
-      run_chunk_with_locale(
-        locale,
-        chunk,
-        import_state.column_map,
-        import_state.custom_field_map,
-        opts,
-        live_view_pid,
-        idx
-      )
-    else
-      Task.Supervisor.start_child(
-        Mv.TaskSupervisor,
-        fn ->
-          run_chunk_with_locale(
-            locale,
-            chunk,
-            import_state.column_map,
-            import_state.custom_field_map,
-            opts,
-            live_view_pid,
-            idx
-          )
-        end
-      )
-    end
+    _ =
+      if Config.sql_sandbox?() do
+        run_chunk_with_locale(
+          locale,
+          chunk,
+          import_state.column_map,
+          import_state.custom_field_map,
+          opts,
+          live_view_pid,
+          idx
+        )
+      else
+        Task.Supervisor.start_child(
+          Mv.TaskSupervisor,
+          fn ->
+            run_chunk_with_locale(
+              locale,
+              chunk,
+              import_state.column_map,
+              import_state.custom_field_map,
+              opts,
+              live_view_pid,
+              idx
+            )
+          end
+        )
+      end
 
     {:noreply, socket}
   end
@@ -378,7 +308,7 @@ defmodule MvWeb.ImportLive do
          live_view_pid,
          idx
        ) do
-    Gettext.put_locale(MvWeb.Gettext, locale)
+    _ = Gettext.put_locale(MvWeb.Gettext, locale)
     ImportRunner.process_chunk(chunk, column_map, custom_field_map, opts, live_view_pid, idx)
   end