Users list and show: Role, Password, OIDC columns; UserHelpers

- Index: load :role; columns Role, Password (has_password?), OIDC; contrast fix.
- Show: Role, OIDC (Linked/Not linked); has_password? for Password Authentication.
- UserHelpers: has_password?/1, has_oidc?/1. Gettext: new strings and DE translations.

lib/mv_web/helpers/user_helpers.ex

@@ -0,0 +1,58 @@
+defmodule MvWeb.Helpers.UserHelpers do
+  @moduledoc """
+  Helper functions for user-related display in the web layer.
+
+  Provides utilities for showing authentication status without exposing
+  sensitive attributes (e.g. hashed_password).
+  """
+
+  @doc """
+  Returns whether the user has password authentication set.
+
+  Only returns true when `hashed_password` is a non-empty string. This avoids
+  treating `nil`, empty string, or forbidden/redacted values (e.g. when the
+  attribute is not visible to the actor) as "has password".
+
+  ## Examples
+
+      iex> user = %{hashed_password: nil}
+      iex> MvWeb.Helpers.UserHelpers.has_password?(user)
+      false
+
+      iex> user = %{hashed_password: "$2b$12$..."}
+      iex> MvWeb.Helpers.UserHelpers.has_password?(user)
+      true
+
+      iex> user = %{hashed_password: ""}
+      iex> MvWeb.Helpers.UserHelpers.has_password?(user)
+      false
+  """
+  @spec has_password?(map() | struct()) :: boolean()
+  def has_password?(user) when is_map(user) do
+    case Map.get(user, :hashed_password) do
+      hash when is_binary(hash) and byte_size(hash) > 0 -> true
+      _ -> false
+    end
+  end
+
+  @doc """
+  Returns whether the user is linked via OIDC/SSO (has a non-empty oidc_id).
+
+  ## Examples
+
+      iex> user = %{oidc_id: nil}
+      iex> MvWeb.Helpers.UserHelpers.has_oidc?(user)
+      false
+
+      iex> user = %{oidc_id: "sub-from-rauthy"}
+      iex> MvWeb.Helpers.UserHelpers.has_oidc?(user)
+      true
+  """
+  @spec has_oidc?(map() | struct()) :: boolean()
+  def has_oidc?(user) when is_map(user) do
+    case Map.get(user, :oidc_id) do
+      id when is_binary(id) and byte_size(id) > 0 -> true
+      _ -> false
+    end
+  end
+end