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/contact_notifier_test.exs

@@ -0,0 +1,87 @@
+defmodule Berrypod.ContactNotifierTest do
+  use Berrypod.DataCase, async: true
+
+  import Swoosh.TestAssertions
+
+  alias Berrypod.ContactNotifier
+  alias Berrypod.Settings
+
+  describe "deliver_contact_message/1" do
+    test "sends email with valid params" do
+      assert {:ok, _} =
+               ContactNotifier.deliver_contact_message(%{
+                 "name" => "Jo Bloggs",
+                 "email" => "jo@example.com",
+                 "subject" => "Question about prints",
+                 "message" => "Do you ship to Mars?"
+               })
+
+      assert_email_sent(fn email ->
+        assert email.subject =~ "Question about prints"
+        assert email.text_body =~ "Jo Bloggs"
+        assert email.text_body =~ "jo@example.com"
+        assert email.text_body =~ "Do you ship to Mars?"
+        assert {"", "jo@example.com"} = email.reply_to
+      end)
+    end
+
+    test "sends to contact_email when set" do
+      Settings.put_setting("contact_email", "shop@example.com")
+
+      assert {:ok, _} =
+               ContactNotifier.deliver_contact_message(%{
+                 "name" => "Test",
+                 "email" => "test@example.com",
+                 "message" => "Hello"
+               })
+
+      assert_email_sent(fn email ->
+        assert [{"", "shop@example.com"}] = email.to
+      end)
+    end
+
+    test "uses default subject when not provided" do
+      assert {:ok, _} =
+               ContactNotifier.deliver_contact_message(%{
+                 "name" => "Test",
+                 "email" => "test@example.com",
+                 "message" => "Hello"
+               })
+
+      assert_email_sent(fn email ->
+        assert email.subject =~ "Contact form message"
+      end)
+    end
+
+    test "returns error for missing name" do
+      assert {:error, :invalid_params} =
+               ContactNotifier.deliver_contact_message(%{
+                 "name" => "",
+                 "email" => "test@example.com",
+                 "message" => "Hello"
+               })
+    end
+
+    test "returns error for missing email" do
+      assert {:error, :invalid_params} =
+               ContactNotifier.deliver_contact_message(%{
+                 "name" => "Test",
+                 "email" => "",
+                 "message" => "Hello"
+               })
+    end
+
+    test "returns error for missing message" do
+      assert {:error, :invalid_params} =
+               ContactNotifier.deliver_contact_message(%{
+                 "name" => "Test",
+                 "email" => "test@example.com",
+                 "message" => ""
+               })
+    end
+
+    test "returns error for missing keys" do
+      assert {:error, :invalid_params} = ContactNotifier.deliver_contact_message(%{})
+    end
+  end
+end