feat: SEO altyapısı + admin editör/favicon/menü düzeltmeleri

Admin & site:
- @tailwindcss/typography ekle → editör ve yayın içeriği prose stilleriyle düzgün render
- Favicon: logo.png'den kare app/icon.png + apple-icon.png, varsayılan favicon.ico kaldırıldı
- SEO keyword: seo_settings.default_keywords + seo_pages.keywords + buildMetadata birleştirme
- Menü düzeni admin'den yönetilebilir (site_settings.nav_items, /admin/menu, header & mobile-menu refactor)

SEO:
- app/sitemap.ts (statik + blog/hizmet/çözüm/proje/sektör dinamik)
- app/robots.ts (sitemap ref + /admin,/api disallow)
- app/llms.txt/route.ts (AI/LLM rehberi)
- BlogPosting/Service/FAQ/Article JSON-LD wire (json-ld bileşenleri bağlandı)
- buildMetadata: blog/proje OG görseli + type article + keywords birleştirme düzeltmesi
- blog tags → keyword

components/json-ld.tsx

@@ -1,4 +1,5 @@
 import type {
+  BlogPostRow,
   ProjectRow,
   ServiceRow,
   SiteSettingsRow,
@@ -6,6 +7,12 @@ import type {
 } from "@/lib/types";
 import { siteConfig } from "@/lib/site-config";
 
+function absUrl(url?: string | null): string | undefined {
+  if (!url) return undefined;
+  if (url.startsWith("http")) return url;
+  return `${siteConfig.url}${url.startsWith("/") ? "" : "/"}${url}`;
+}
+
 export function JsonLd({ data }: { data: object }) {
   return (
     <script
@@ -137,6 +144,44 @@ export function BreadcrumbLd({
   );
 }
 
+export function BlogPostingLd({
+  post,
+  settings,
+}: {
+  post: BlogPostRow;
+  settings?: SiteSettingsRow | null;
+}) {
+  const image = absUrl(post.seo_image || post.cover_image) ?? `${siteConfig.url}/logo.png`;
+  const url = `${siteConfig.url}/blog/${post.slug}`;
+  const data: Record<string, unknown> = {
+    "@context": "https://schema.org",
+    "@type": "BlogPosting",
+    headline: post.title,
+    description: post.seo_description || post.excerpt || undefined,
+    image,
+    datePublished: post.published_at ?? post.$createdAt,
+    dateModified: post.$updatedAt,
+    author: {
+      "@type": post.author ? "Person" : "Organization",
+      name: post.author || settings?.site_name || siteConfig.name,
+    },
+    publisher: {
+      "@type": "Organization",
+      name: settings?.site_name ?? siteConfig.name,
+      logo: {
+        "@type": "ImageObject",
+        url: `${siteConfig.url}/logo.png`,
+      },
+    },
+    mainEntityOfPage: { "@type": "WebPage", "@id": url },
+    url,
+  };
+  if (post.tags && post.tags.length > 0) {
+    data.keywords = post.tags.join(", ");
+  }
+  return <JsonLd data={data} />;
+}
+
 export function ArticleLd({ post }: { post: ProjectRow }) {
   return (
     <JsonLd