feat: add two-factor view helpers and locale strings

Add two_factor_method_links helper to DeviseHelper for rendering
switch links between 2FA methods. Add locale strings for session
expired, sign-in not initiated, and password reset 2FA required.

Author: santiagorodriguez96

app/helpers/devise_helper.rb

@@ -2,4 +2,8 @@
 
 # Keeping the helper around for backward compatibility.
 module DeviseHelper
+  def two_factor_method_links(resource, current_method)
+    methods = resource.enabled_two_factors - [current_method]
+    safe_join(methods.map { |method| render "devise/two_factor/#{method}_link" })
+  end
 end

app/views/devise/two_factor/_test_otp.html.erb

@@ -0,0 +1,4 @@
+<%= form_tag(two_factor_path(resource_name), method: :post) do %>
+  <%= text_field_tag :otp_attempt %>
+  <%= submit_tag "Verify" %>
+<% end %>

app/views/devise/two_factor/_test_otp_link.html.erb

@@ -0,0 +1 @@
+<%= link_to "Use OTP instead", new_two_factor_challenge_path(resource_name, :test_otp) %>

config/locales/en.yml

@@ -16,6 +16,8 @@ en:
       timeout: "Your session expired. Please sign in again to continue."
       unauthenticated: "You need to sign in or sign up before continuing."
       unconfirmed: "You have to confirm your email address before continuing."
+      two_factor_session_expired: "Your two-factor authentication session has expired. Please sign in again."
+      sign_in_not_initiated: "Please sign in first."
     mailer:
       confirmation_instructions:
         subject: "Confirmation instructions"
@@ -36,6 +38,7 @@ en:
       send_paranoid_instructions: "If your email address exists in our database, you will receive a password recovery link at your email address in a few minutes."
       updated: "Your password has been changed successfully. You are now signed in."
       updated_not_active: "Your password has been changed successfully."
+      updated_two_factor_required: "Your password has been changed successfully. Please complete two-factor authentication."
     registrations:
       destroyed: "Bye! Your account has been successfully cancelled. We hope to see you again soon."
       signed_up: "Welcome! You have signed up successfully."