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.

app/(site)/blog/page.tsx

@@ -0,0 +1,84 @@
+import Image from "next/image";
+import Link from "next/link";
+import type { Metadata } from "next";
+import { ArrowRight, Calendar } from "lucide-react";
+import { SectionTitle } from "@/components/section-title";
+import { listPublishedPosts } from "@/lib/data";
+import { buildMetadata } from "@/lib/seo";
+
+export async function generateMetadata(): Promise<Metadata> {
+  return buildMetadata("/blog", {
+    title: "Blog",
+    description: "Yazılım, web tasarım, SEO ve dijital pazarlama üzerine yazılar.",
+  });
+}
+
+export default async function BlogIndex() {
+  const posts = await listPublishedPosts();
+
+  return (
+    <div className="mx-auto max-w-7xl px-6 py-20">
+      <SectionTitle
+        eyebrow="Blog"
+        title="Yazılım, tasarım ve büyüme üzerine"
+        description="Sektörden notlar, vaka çalışmaları ve teknik rehberler."
+      />
+
+      <div className="mt-14">
+        {posts.length === 0 ? (
+          <div className="rounded-2xl border border-dashed border-[var(--border)] bg-[var(--navy-50)]/40 p-12 text-center">
+            <p className="text-sm text-[var(--muted)]">
+              Henüz yayınlanmış yazı yok.
+            </p>
+          </div>
+        ) : (
+          <div className="grid gap-8 md:grid-cols-2 lg:grid-cols-3">
+            {posts.map((p) => (
+              <article
+                key={p.$id}
+                className="group overflow-hidden rounded-2xl border border-[var(--border)] bg-white transition hover:shadow-lg"
+              >
+                <Link href={`/blog/${p.slug}`}>
+                  <div className="relative aspect-video overflow-hidden bg-[var(--navy-50)]">
+                    {p.cover_image ? (
+                      <Image
+                        src={p.cover_image}
+                        alt={p.title}
+                        fill
+                        sizes="(min-width: 1024px) 33vw, (min-width: 768px) 50vw, 100vw"
+                        className="object-cover transition group-hover:scale-105"
+                      />
+                    ) : (
+                      <div className="flex h-full items-center justify-center text-3xl font-bold text-[var(--navy)]/30">
+                        {p.title.charAt(0)}
+                      </div>
+                    )}
+                  </div>
+                  <div className="p-6">
+                    <p className="flex items-center gap-1.5 text-xs text-[var(--muted)]">
+                      <Calendar className="size-3.5" />
+                      {p.published_at
+                        ? new Date(p.published_at).toLocaleDateString("tr-TR")
+                        : "—"}
+                    </p>
+                    <h3 className="mt-2 text-lg font-semibold text-[var(--navy)] group-hover:text-[var(--sky-600)]">
+                      {p.title}
+                    </h3>
+                    {p.excerpt && (
+                      <p className="mt-2 text-sm leading-relaxed text-[var(--muted)] line-clamp-3">
+                        {p.excerpt}
+                      </p>
+                    )}
+                    <span className="mt-4 inline-flex items-center gap-1 text-sm font-medium text-[var(--sky-600)]">
+                      Devamını oku <ArrowRight className="size-3.5" />
+                    </span>
+                  </div>
+                </Link>
+              </article>
+            ))}
+          </div>
+        )}
+      </div>
+    </div>
+  );
+}