consolidate shop pages into unified LiveView for editor state persistence

Replace individual shop LiveViews with a single Shop.Page that dispatches
to page modules based on live_action. This enables patch navigation between
pages, preserving socket state (including editor state) across transitions.

Changes:
- Add Shop.Page unified LiveView with handle_params dispatch
- Extract page logic into Shop.Pages.* modules (Home, Product, Collection, etc.)
- Update router to use Shop.Page with live_action for all shop routes
- Change navigate= to patch= in shop component links
- Add maybe_sync_editing_blocks to reload editor state when page changes
- Track editor_page_slug to detect cross-page navigation while editing
- Fix picture element height when hover image disabled
- Extract ThemeEditor components for shared use

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

lib/berrypod_web/live/shop/pages/content.ex

@@ -0,0 +1,79 @@
+defmodule BerrypodWeb.Shop.Pages.Content do
+  @moduledoc """
+  Content page handler for the unified Shop.Page LiveView.
+  Handles about, delivery, privacy, and terms pages.
+  """
+
+  import Phoenix.Component, only: [assign: 2, assign: 3]
+
+  alias Berrypod.LegalPages
+  alias Berrypod.Pages
+  alias Berrypod.Theme.PreviewData
+
+  def init(socket, _params, _uri) do
+    # Content pages load in handle_params based on live_action
+    {:noreply, socket}
+  end
+
+  def handle_params(_params, _uri, socket) do
+    action = socket.assigns.live_action
+    slug = to_string(action)
+    page = Pages.get_page(slug)
+    {seo, content_blocks} = page_config(action)
+
+    socket =
+      socket
+      |> assign(seo)
+      |> assign(:page, page)
+      |> assign(:content_blocks, content_blocks)
+
+    {:noreply, socket}
+  end
+
+  def handle_event(_event, _params, _socket), do: :cont
+
+  # Returns {seo_assigns, content_blocks} for each content page
+  defp page_config(:about) do
+    {
+      %{
+        page_title: "About",
+        page_description: "Your story goes here – this is sample content for the demo shop",
+        og_url: BerrypodWeb.Endpoint.url() <> "/about"
+      },
+      PreviewData.about_content()
+    }
+  end
+
+  defp page_config(:delivery) do
+    {
+      %{
+        page_title: "Delivery & returns",
+        page_description: "Everything you need to know about shipping and returns.",
+        og_url: BerrypodWeb.Endpoint.url() <> "/delivery"
+      },
+      LegalPages.delivery_content()
+    }
+  end
+
+  defp page_config(:privacy) do
+    {
+      %{
+        page_title: "Privacy policy",
+        page_description: "How we handle your personal information.",
+        og_url: BerrypodWeb.Endpoint.url() <> "/privacy"
+      },
+      LegalPages.privacy_content()
+    }
+  end
+
+  defp page_config(:terms) do
+    {
+      %{
+        page_title: "Terms of service",
+        page_description: "The terms and conditions governing purchases from our shop.",
+        og_url: BerrypodWeb.Endpoint.url() <> "/terms"
+      },
+      LegalPages.terms_content()
+    }
+  end
+end