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/page_renderer.ex

@@ -310,8 +310,18 @@ defmodule BerrypodWeb.PageRenderer do
       |> assign(:title, settings["title"] || "Newsletter")
       |> assign(:description, settings["description"] || "")
       |> assign(:button_text, settings["button_text"] || "Subscribe")
+      |> assign(:newsletter_state, assigns[:newsletter_state] || :idle)
+      |> assign(:newsletter_enabled, assigns[:newsletter_enabled] || false)
 
-    ~H"<.newsletter_card title={@title} description={@description} button_text={@button_text} />"
+    ~H"""
+    <.newsletter_card
+      title={@title}
+      description={@description}
+      button_text={@button_text}
+      newsletter_state={@newsletter_state}
+      newsletter_enabled={@newsletter_enabled}
+    />
+    """
   end
 
   defp render_block(%{block: %{"type" => "social_links_card"}} = assigns) do