add no-JS contact form and noscript banner

Wire up the contact form with action/method/name attrs so it works
without JavaScript. Add ContactNotifier, ContactController, and a
noscript info banner in the shop root layout.

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

test/berrypod_web/controllers/contact_controller_test.exs

@@ -0,0 +1,48 @@
+defmodule BerrypodWeb.ContactControllerTest do
+  use BerrypodWeb.ConnCase, async: false
+
+  import Berrypod.AccountsFixtures
+  import Swoosh.TestAssertions
+
+  setup do
+    user_fixture()
+    {:ok, _} = Berrypod.Settings.set_site_live(true)
+    # Clear confirmation email from user_fixture
+    Swoosh.TestAssertions.assert_email_sent()
+    :ok
+  end
+
+  describe "POST /contact/send" do
+    test "sends email and redirects with success flash", %{conn: conn} do
+      conn =
+        post(conn, ~p"/contact/send", %{
+          "name" => "Jo Bloggs",
+          "email" => "jo@example.com",
+          "subject" => "Question",
+          "message" => "Do you ship internationally?"
+        })
+
+      assert redirected_to(conn) == "/contact"
+      assert Phoenix.Flash.get(conn.assigns.flash, :info) =~ "Message sent"
+
+      assert_email_sent(fn email ->
+        assert email.subject =~ "Question"
+        assert email.text_body =~ "Do you ship internationally?"
+      end)
+    end
+
+    test "redirects with error flash when required fields missing", %{conn: conn} do
+      conn = post(conn, ~p"/contact/send", %{"name" => "", "email" => "", "message" => ""})
+
+      assert redirected_to(conn) == "/contact"
+      assert Phoenix.Flash.get(conn.assigns.flash, :error) =~ "required fields"
+    end
+
+    test "redirects with error flash when params empty", %{conn: conn} do
+      conn = post(conn, ~p"/contact/send", %{})
+
+      assert redirected_to(conn) == "/contact"
+      assert Phoenix.Flash.get(conn.assigns.flash, :error) =~ "required fields"
+    end
+  end
+end