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.

components/testimonials.tsx

@@ -0,0 +1,50 @@
+import { Quote, Star } from "lucide-react";
+import Image from "next/image";
+import type { TestimonialRow } from "@/lib/types";
+
+export function TestimonialsCarousel({ items }: { items: TestimonialRow[] }) {
+  return (
+    <div className="grid gap-6 md:grid-cols-2 lg:grid-cols-3">
+      {items.map((t) => (
+        <figure
+          key={t.$id}
+          className="relative rounded-2xl border border-[var(--border)] bg-white p-6"
+        >
+          <Quote
+            className="absolute right-5 top-5 size-8 text-[var(--sky-50)]"
+            aria-hidden
+          />
+          <div className="flex items-center gap-0.5 text-amber-500">
+            {Array.from({ length: t.rating ?? 5 }).map((_, i) => (
+              <Star key={i} className="size-3.5 fill-current" />
+            ))}
+          </div>
+          <blockquote className="mt-4 text-sm leading-relaxed text-[var(--foreground)]">
+            “{t.message}”
+          </blockquote>
+          <figcaption className="mt-5 flex items-center gap-3 border-t border-[var(--border)] pt-4">
+            {t.image_url ? (
+              <Image
+                src={t.image_url}
+                alt={t.name}
+                width={40}
+                height={40}
+                className="rounded-full object-cover"
+              />
+            ) : (
+              <div className="flex size-10 items-center justify-center rounded-full bg-[var(--navy-50)] text-sm font-semibold text-[var(--navy)]">
+                {t.name.charAt(0)}
+              </div>
+            )}
+            <div>
+              <p className="text-sm font-semibold text-[var(--navy)]">{t.name}</p>
+              <p className="text-xs text-[var(--muted)]">
+                {[t.role, t.company].filter(Boolean).join(" — ")}
+              </p>
+            </div>
+          </figcaption>
+        </figure>
+      ))}
+    </div>
+  );
+}