complete reviews system (phases 4-6)

- review display: photos with lightbox, verified badge, pagination
- admin moderation: pending/approved/rejected tabs, bulk actions, nav badge
- SEO: JSON-LD AggregateRating and Review markup on product pages
- automation: review request emails 7 days after delivery (Oban worker)
- rating cache: avg/count fields on products, updated on approval
- fix file size validation in media test (10MB limit)

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

lib/berrypod_web/components/layouts/admin.html.heex

@@ -126,6 +126,20 @@
                 <.icon name="hero-photo" class="size-5" /> Media
               </.link>
             </li>
+            <li>
+              <.link
+                navigate={~p"/admin/reviews"}
+                class={admin_nav_active?(@current_path, "/admin/reviews")}
+              >
+                <.icon name="hero-star" class="size-5" /> Reviews
+                <span
+                  :if={@pending_review_count > 0}
+                  class="admin-badge admin-badge-sm admin-badge-warning ml-auto"
+                >
+                  {@pending_review_count}
+                </span>
+              </.link>
+            </li>
             <li>
               <.link
                 navigate={~p"/admin/newsletter"}