add admin CRUD for custom CMS pages

New settings form for creating and editing custom page metadata
(title, slug, meta description, published, nav settings). Pages
index shows custom pages section with draft badges and delete.
Editor shows settings button for custom pages, hides reset to
defaults. 20 new tests.

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

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

@@ -2,7 +2,7 @@ defmodule BerrypodWeb.Admin.Pages.Editor do
   use BerrypodWeb, :live_view
 
   alias Berrypod.{Media, Pages}
-  alias Berrypod.Pages.{BlockEditor, BlockTypes}
+  alias Berrypod.Pages.{BlockEditor, BlockTypes, Page}
   alias Berrypod.Products.ProductImage
   alias Berrypod.Theme.{Fonts, PreviewData}
 
@@ -38,7 +38,8 @@ defmodule BerrypodWeb.Admin.Pages.Editor do
      |> assign(:image_picker_block_id, nil)
      |> assign(:image_picker_field_key, nil)
      |> assign(:image_picker_images, [])
-     |> assign(:image_picker_search, "")}
+     |> assign(:image_picker_search, "")
+     |> assign(:is_custom_page, !Page.system_slug?(slug))}
   end
 
   # ── Block manipulation events ────────────────────────────────────
@@ -310,7 +311,15 @@ defmodule BerrypodWeb.Admin.Pages.Editor do
             />
             {if @show_preview, do: "Edit", else: "Preview"}
           </button>
+          <.link
+            :if={@is_custom_page}
+            navigate={~p"/admin/pages/#{@slug}/settings"}
+            class="admin-btn admin-btn-sm admin-btn-ghost"
+          >
+            <.icon name="hero-cog-6-tooth" class="size-4" /> Settings
+          </.link>
           <button
+            :if={!@is_custom_page}
             phx-click="reset_defaults"
             data-confirm="Reset this page to its default layout? Your changes will be lost."
             class="admin-btn admin-btn-sm admin-btn-ghost"