fix email settings: missing providers, a11y, no-JS support

show all 10 providers in three groups (popular, transactional,
advanced) with category headings. fix phx-change clobbering text
fields, async test email sending state, integer parse crash on
bad port. add keyboard focus on card radios, fieldset legend,
WCAG-compliant badge contrast, responsive grid. extract shared
save_config into Mailer, add no-JS controller fallback with
configured_adapter hidden field for adapter change detection.
remove CardRadioScroll JS hook (no longer needed).

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

lib/berrypod_web/controllers/email_settings_controller.ex

@@ -0,0 +1,54 @@
+defmodule BerrypodWeb.EmailSettingsController do
+  @moduledoc """
+  No-JS fallback for email settings form submission.
+
+  With JS enabled, the LiveView handles everything. Without JS,
+  the form POSTs here and we redirect back to the LiveView page.
+  """
+  use BerrypodWeb, :controller
+
+  alias Berrypod.Mailer
+
+  def update(conn, %{"email" => params}) do
+    selected = params["adapter"]
+    configured = params["configured_adapter"]
+
+    if selected != configured do
+      # User changed adapter radio but config fields are for the old adapter.
+      # Redirect to show the new adapter's config fields.
+      redirect(conn, to: ~p"/admin/settings/email?adapter=#{selected}")
+    else
+      case Mailer.save_config(selected, params, conn.assigns.current_scope.user.email) do
+        {:ok, _adapter_info} ->
+          conn
+          |> put_flash(:info, "Settings saved — send a test email to check it works")
+          |> redirect(to: ~p"/admin/settings/email")
+
+        {:error, field_errors} when is_map(field_errors) ->
+          message = field_errors |> Map.values() |> Enum.join(". ")
+
+          conn
+          |> put_flash(:error, message)
+          |> redirect(to: ~p"/admin/settings/email?adapter=#{selected}")
+      end
+    end
+  end
+
+  def test(conn, _params) do
+    user = conn.assigns.current_scope.user
+
+    case Mailer.send_test_email(user.email, Mailer.from_address()) do
+      {:ok, _} ->
+        Mailer.mark_email_verified()
+
+        conn
+        |> put_flash(:info, "Test email sent to #{user.email}")
+        |> redirect(to: ~p"/admin/settings/email")
+
+      {:error, reason} ->
+        conn
+        |> put_flash(:error, Mailer.friendly_error(reason))
+        |> redirect(to: ~p"/admin/settings/email")
+    end
+  end
+end