add SEO enhancements: OG images, meta robots, FAQ block, image sitemap

- Per-page SEO controls: meta robots directives, focus keyword, OG image
- Site-wide default OG image in admin settings
- FAQ block type with FAQPage JSON-LD schema
- Enhanced Organization JSON-LD with business info, contact, address
- Image sitemap with product images
- SEO preview panel with Google/social card mockups
- SEO checklist with real-time scoring
- Business info section in site editor
- GSC integration scaffolding (OAuth, client, cache)

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

lib/berrypod_web/page_renderer.ex

@@ -801,6 +801,39 @@ defmodule BerrypodWeb.PageRenderer do
     """
   end
 
+  defp render_block(%{block: %{"type" => "faq"}} = assigns) do
+    settings = assigns.block["settings"] || %{}
+    title = settings["title"] || ""
+
+    items =
+      (settings["items"] || [])
+      |> Enum.filter(fn item ->
+        q = item["question"] || ""
+        String.trim(q) != ""
+      end)
+
+    assigns =
+      assigns
+      |> assign(:faq_title, title)
+      |> assign(:items, items)
+
+    ~H"""
+    <section class="faq-section page-container">
+      <h2 :if={@faq_title != ""} class="faq-title">{@faq_title}</h2>
+      <dl class="faq-list">
+        <details :for={item <- @items} class="faq-item">
+          <summary class="faq-question">{item["question"]}</summary>
+          <div class="faq-answer">
+            <p :for={para <- String.split(item["answer"] || "", ~r/\n{2,}/, trim: true)}>
+              {para}
+            </p>
+          </div>
+        </details>
+      </dl>
+    </section>
+    """
+  end
+
   defp render_block(%{block: %{"type" => "trust_badges"}} = assigns) do
     ~H"""
     <.trust_badges :if={@theme_settings.pdp_trust_badges} />