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>

assets/css/shop/components.css

@@ -3658,3 +3658,77 @@
     text-decoration: underline;
   }
 }
+
+/* ── FAQ section ── */
+
+@layer components {
+  .faq-section {
+    padding-block: var(--t-space-section, 3rem);
+  }
+
+  .faq-title {
+    font-family: var(--t-font-heading);
+    font-weight: var(--t-heading-weight);
+    font-size: var(--t-text-2xl, 1.5rem);
+    letter-spacing: var(--t-heading-tracking);
+    color: var(--t-text-primary);
+    margin-bottom: 1.5rem;
+  }
+
+  .faq-list {
+    display: flex;
+    flex-direction: column;
+    gap: 0;
+  }
+
+  .faq-item {
+    border-top: 1px solid var(--t-border-subtle);
+
+    &:last-child {
+      border-bottom: 1px solid var(--t-border-subtle);
+    }
+  }
+
+  .faq-question {
+    display: flex;
+    align-items: center;
+    justify-content: space-between;
+    cursor: pointer;
+    padding: 1rem 0;
+    font-size: var(--t-text-base, 1rem);
+    font-weight: 500;
+    color: var(--t-text-primary);
+    list-style: none;
+
+    &::-webkit-details-marker {
+      display: none;
+    }
+
+    &::after {
+      content: "+";
+      font-size: 1.25rem;
+      font-weight: 400;
+      color: var(--t-text-secondary);
+      transition: transform 0.2s ease;
+    }
+  }
+
+  .faq-item[open] .faq-question::after {
+    content: "−";
+  }
+
+  .faq-answer {
+    padding-bottom: 1rem;
+    color: var(--t-text-secondary);
+    font-size: var(--t-text-base, 1rem);
+    line-height: 1.6;
+
+    p {
+      margin: 0;
+
+      + p {
+        margin-top: 0.75rem;
+      }
+    }
+  }
+}