add newsletter and email campaigns

Subscribers with double opt-in confirmation, campaign composer with
draft/scheduled/sent lifecycle, admin dashboard with overview stats,
CSV export, and shop signup form wired into page builder blocks.

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

lib/berrypod_web/newsletter_hook.ex

@@ -0,0 +1,60 @@
+defmodule BerrypodWeb.NewsletterHook do
+  @moduledoc """
+  LiveView on_mount hook for newsletter signup across all shop pages.
+
+  Uses `attach_hook/4` to intercept `newsletter_subscribe` events globally
+  without modifying individual shop LiveViews.
+  """
+
+  import Phoenix.Component, only: [assign: 3]
+  import Phoenix.LiveView, only: [attach_hook: 4]
+
+  alias Berrypod.Newsletter
+
+  def on_mount(:mount_newsletter, _params, _session, socket) do
+    enabled = Newsletter.newsletter_enabled?()
+
+    socket =
+      socket
+      |> assign(:newsletter_enabled, enabled)
+      |> assign(:newsletter_state, :idle)
+      |> assign(:newsletter_ip_hash, hash_ip(socket))
+      |> attach_hook(:newsletter, :handle_event, &handle_newsletter_event/3)
+
+    {:cont, socket}
+  end
+
+  defp handle_newsletter_event("newsletter_subscribe", %{"email" => email}, socket) do
+    if socket.assigns.newsletter_enabled do
+      case Newsletter.subscribe(email,
+             consent_text: "Newsletter signup on website",
+             ip_hash: socket.assigns.newsletter_ip_hash
+           ) do
+        {:ok, _} ->
+          {:halt, assign(socket, :newsletter_state, :submitted)}
+
+        {:already_confirmed, _} ->
+          {:halt, assign(socket, :newsletter_state, :submitted)}
+
+        {:error, _} ->
+          {:halt, assign(socket, :newsletter_state, :error)}
+      end
+    else
+      {:halt, assign(socket, :newsletter_state, :disabled)}
+    end
+  end
+
+  defp handle_newsletter_event(_event, _params, socket), do: {:cont, socket}
+
+  # connect_info is only available during mount, so we hash and store it early
+  defp hash_ip(socket) do
+    case Phoenix.LiveView.get_connect_info(socket, :peer_data) do
+      %{address: ip} ->
+        daily_salt = Date.utc_today() |> Date.to_iso8601()
+        :crypto.hash(:sha256, :inet.ntoa(ip) ++ [daily_salt]) |> Base.encode16(case: :lower)
+
+      _ ->
+        nil
+    end
+  end
+end