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/admin/(protected)/referanslar/form.tsx

@@ -0,0 +1,64 @@
+import { Save } from "lucide-react";
+import {
+  Checkbox,
+  Field,
+  FormActions,
+  FormShell,
+  GhostLink,
+  PageHeader,
+  PrimaryButton,
+  Textarea,
+} from "@/components/admin/form";
+import { saveTestimonial } from "@/lib/admin-actions";
+import type { TestimonialRow } from "@/lib/types";
+
+export function TestimonialForm({ row }: { row?: TestimonialRow }) {
+  return (
+    <div>
+      <PageHeader
+        title={row ? "Referansı düzenle" : "Yeni referans"}
+        backHref="/admin/referanslar"
+      />
+      <form action={saveTestimonial}>
+        {row && <input type="hidden" name="id" value={row.$id} />}
+        <FormShell>
+          <div className="grid gap-5 md:grid-cols-2">
+            <Field label="İsim" name="name" required defaultValue={row?.name} />
+            <Field label="Görsel URL" name="image_url" type="url" defaultValue={row?.image_url} />
+            <Field label="Pozisyon" name="role" defaultValue={row?.role} />
+            <Field label="Firma" name="company" defaultValue={row?.company} />
+            <Field
+              label="Puan (1–5)"
+              name="rating"
+              type="number"
+              defaultValue={row?.rating ?? 5}
+            />
+            <Field label="Sıra" name="order" type="number" defaultValue={row?.order ?? 0} />
+          </div>
+          <div className="mt-5">
+            <Textarea
+              label="Yorum"
+              name="message"
+              required
+              rows={5}
+              defaultValue={row?.message}
+            />
+          </div>
+          <div className="mt-5">
+            <Checkbox
+              label="Öne çıkar"
+              name="featured"
+              defaultChecked={row?.featured ?? false}
+            />
+          </div>
+          <FormActions>
+            <GhostLink href="/admin/referanslar">İptal</GhostLink>
+            <PrimaryButton>
+              <Save className="size-4" /> Kaydet
+            </PrimaryButton>
+          </FormActions>
+        </FormShell>
+      </form>
+    </div>
+  );
+}