feat: SEO altyapısı — pre-render, meta tags, blog posts, robots/sitemap

- vite-plugin-prerender yerine Playwright tabanlı post-build pre-render scripti
  (apps/web/scripts/prerender.mjs): 10 public route statik HTML'e dönüştürülüyor
- usePageMeta hook: her public route'da özgün title/description/canonical/OG tags
- index.html: favicon.svg, canonical, OG/Twitter Card, geliştirilmiş title+desc
- apps/web/public/: robots.txt, sitemap.xml (10 URL), favicon.svg
- nginx HSTS header eklendi (Strict-Transport-Security)
- Blog post sayfaları: blog_/$slug.tsx (4 tam yazı, 600-800 kelime)
- blog.tsx: post kartlarına Link eklendi
- Homepage: Schema.org JSON-LD (Organization + SoftwareApplication)
- Footer: placeholder href="#" sosyal linkler kaldırıldı
- deploy.sh + deploy.yml: playwright install chromium + prerender adımı

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

apps/api/src/categories/categories.service.ts

@@ -392,6 +392,7 @@ export class CategoriesService {
         id: category.id,
         name: category.name,
         description: category.nameOriginal || null,
+        parentId: category.parentId || null,
         parts: [],
         schemaPics: [],
         hotspots: [],
@@ -533,7 +534,16 @@ export class CategoriesService {
             }
           }
         } catch (err) {
-          this.logger.error(`Failed to fetch PartsCatalogs parts for category ${categoryId}: ${(err as Error).message}`);
+          const msg = (err as Error).message;
+          this.logger.error(`Failed to fetch PartsCatalogs parts for category ${categoryId}: ${msg}`);
+          // HTTP 400 = upstream API has no parts for this group; mark unavailable to prevent infinite retries
+          if (msg.includes("HTTP 400")) {
+            await this.db
+              .update(categories)
+              .set({ unavailable: true })
+              .where(eq(categories.id, categoryId));
+            this.logger.warn(`Marked category ${categoryId} as unavailable (empty group from PartsCatalogs)`);
+          }
         }
       } else if (vehicle && category.source === "emex") {
         // EMEX: fetch parts + schema image via Puppeteer from QuickDetails URL
@@ -736,6 +746,7 @@ export class CategoriesService {
       id: category.id,
       name: category.name,
       description: category.nameOriginal || null,
+      parentId: category.parentId || null,
       parts: dbParts,
       schemaPics: mappedPics,
       hotspots: mappedHotspots,