add admin page editor with block reordering and management

Stage 6 of the page builder: admin UI at /admin/pages for managing
page layouts. Page list shows all 14 pages grouped by category.
Editor supports reorder (up/down), add, remove, duplicate, save,
and reset to defaults. DirtyGuard JS hook warns on unsaved changes.
ARIA live regions announce block operations for screen readers.

Also: regenerate admin icons (81 rules via mix task with @layer
wrapping), add gen_smtp dep for SMTP email adapter, add :key to
page renderer block loop for correct LiveView diffing.

1309 tests, 0 failures.

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

lib/berrypod_web/live/admin/pages/index.ex

@@ -0,0 +1,75 @@
+defmodule BerrypodWeb.Admin.Pages.Index do
+  use BerrypodWeb, :live_view
+
+  alias Berrypod.Pages
+
+  @page_groups [
+    {"Marketing", ~w(home about contact)},
+    {"Legal", ~w(delivery privacy terms)},
+    {"Shop", ~w(collection pdp cart search)},
+    {"Orders", ~w(checkout_success orders order_detail)},
+    {"System", ~w(error)}
+  ]
+
+  @impl true
+  def mount(_params, _session, socket) do
+    pages = Pages.list_pages() |> Map.new(&{&1.slug, &1})
+
+    {:ok,
+     socket
+     |> assign(:page_title, "Pages")
+     |> assign(:pages, pages)
+     |> assign(:page_groups, @page_groups)}
+  end
+
+  @impl true
+  def render(assigns) do
+    ~H"""
+    <.header>
+      Pages
+      <:subtitle>Customise the layout and content of every page on your shop.</:subtitle>
+    </.header>
+
+    <div class="page-list">
+      <div :for={{group_name, slugs} <- @page_groups} class="page-group">
+        <h3 class="page-group-title">{group_name}</h3>
+        <div class="page-group-cards">
+          <.link
+            :for={slug <- slugs}
+            navigate={~p"/admin/pages/#{slug}"}
+            class="page-card"
+          >
+            <span class="page-card-icon">
+              <.icon name={page_icon(slug)} class="size-5" />
+            </span>
+            <span class="page-card-info">
+              <span class="page-card-title">{@pages[slug].title}</span>
+              <span class="page-card-meta">
+                {length(@pages[slug].blocks)} {if length(@pages[slug].blocks) == 1,
+                  do: "block",
+                  else: "blocks"}
+              </span>
+            </span>
+            <.icon name="hero-chevron-right-mini" class="size-4 page-card-arrow" />
+          </.link>
+        </div>
+      </div>
+    </div>
+    """
+  end
+
+  defp page_icon("home"), do: "hero-home"
+  defp page_icon("about"), do: "hero-user"
+  defp page_icon("contact"), do: "hero-envelope"
+  defp page_icon("delivery"), do: "hero-truck"
+  defp page_icon("privacy"), do: "hero-shield-check"
+  defp page_icon("terms"), do: "hero-document-text"
+  defp page_icon("collection"), do: "hero-tag"
+  defp page_icon("pdp"), do: "hero-cube"
+  defp page_icon("cart"), do: "hero-shopping-cart"
+  defp page_icon("search"), do: "hero-magnifying-glass"
+  defp page_icon("checkout_success"), do: "hero-check-circle"
+  defp page_icon("orders"), do: "hero-clipboard-document-list"
+  defp page_icon("order_detail"), do: "hero-clipboard-document"
+  defp page_icon("error"), do: "hero-exclamation-triangle"
+end