feat: admin paneli + blog + testimonials + SEO yöneticisi

Backend altyapısı:
- 4 yeni Appwrite tablosu: blog_posts, testimonials, seo_pages, seo_settings
- Appwrite Storage bucket: kovak-yazilim-media (görsel yüklemeleri)
- Appwrite Auth ile session cookie tabanlı koruma

Admin paneli (/admin):
- Login akışı (email/password) + protected layout
- Dashboard: sayım kartları + hızlı aksiyonlar
- Blog CRUD: markdown content, kapak görseli, draft/published, SEO alanları
- Services CRUD: lucide ikon seçici
- Projects CRUD: teknoloji etiketleri, live URL
- Testimonials CRUD: puanlama
- SEO yöneticisi: global ayarlar + sayfa bazlı override
- Mesaj inbox: status filtreleme + güncelleme
- Medya kütüphanesi: Appwrite Storage upload/delete

Public:
- /blog ve /blog/[slug] sayfaları (markdown render)
- Anasayfaya Testimonials bölümü
- Tüm public sayfalarda generateMetadata + seo_pages override
- Header'a Blog linki

Route yapısı:
- app/(site)/ — public site, Header/Footer ortak
- app/admin/login — auth dışı
- app/admin/(protected)/ — requireUser() korumalı

23 route üretiliyor, public static, admin dynamic.

lib/types.ts

@@ -21,10 +21,59 @@ export interface ProjectRow extends Models.Row {
   featured?: boolean | null;
 }
 
-export interface ContactMessageInput {
+export interface BlogPostRow extends Models.Row {
+  slug: string;
+  title: string;
+  excerpt?: string | null;
+  content?: string | null;
+  cover_image?: string | null;
+  cover_file_id?: string | null;
+  author?: string | null;
+  status?: "draft" | "published" | null;
+  published_at?: string | null;
+  tags?: string[] | null;
+  seo_title?: string | null;
+  seo_description?: string | null;
+  seo_image?: string | null;
+}
+
+export interface TestimonialRow extends Models.Row {
+  name: string;
+  role?: string | null;
+  company?: string | null;
+  message: string;
+  rating?: number | null;
+  image_url?: string | null;
+  order?: number | null;
+  featured?: boolean | null;
+}
+
+export interface SeoPageRow extends Models.Row {
+  path: string;
+  title?: string | null;
+  description?: string | null;
+  og_image?: string | null;
+  canonical?: string | null;
+  noindex?: boolean | null;
+}
+
+export interface SeoSettingsRow extends Models.Row {
+  site_name?: string | null;
+  site_description?: string | null;
+  default_og_image?: string | null;
+  twitter_handle?: string | null;
+  facebook_url?: string | null;
+  linkedin_url?: string | null;
+  instagram_url?: string | null;
+  google_site_verification?: string | null;
+  gtm_id?: string | null;
+}
+
+export interface ContactMessageRow extends Models.Row {
   name: string;
   email: string;
-  phone?: string;
-  subject?: string;
+  phone?: string | null;
+  subject?: string | null;
   message: string;
+  status?: "new" | "read" | "replied" | "archived" | null;
 }