init: kovakemlak-crm project scaffold

- Next.js 16 + Appwrite multi-tenant emlak CRM
- Database: kovakemlak-db (properties, customers, customer_searches, property_matches, presentations, investors, activities, tenant_settings)
- Same stack as isletmem-kovakcrm (shadcn/ui template base)
- Modules: portföy, müşteri takibi, arama kriterleri, otomatik eşleştirme, sunum linki, yatırımcı portalı

src/app/(auth)/errors/under-maintenance/components/under-maintenance-error.tsx

@@ -0,0 +1,32 @@
+"use client"
+
+import { Button } from "@/components/ui/button"
+import { useRouter } from "next/navigation"
+import Image from "next/image"
+
+export function UnderMaintenanceError() {
+  const router = useRouter()
+
+  return (
+    <div className='mx-auto flex min-h-dvh flex-col items-center justify-center gap-8 p-8 md:gap-12 md:p-16'>
+      <Image
+        src='https://ui.shadcn.com/placeholder.svg'
+        alt='placeholder image'
+        width={960}
+        height={540}
+        className='aspect-video w-240 rounded-xl object-cover dark:brightness-[0.95] dark:invert'
+      />
+      <div className='text-center'>
+        <h1 className='mb-4 text-3xl font-bold'>503</h1>
+        <h2 className="mb-3 text-2xl font-semibold">Under Maintenance</h2>
+        <p>The service is currently unavailable. Please try again later.</p>
+        <div className='mt-6 flex items-center justify-center gap-4 md:mt-8'>
+          <Button className='cursor-pointer' onClick={() => router.push('/dashboard')}>Go Back Home</Button>
+          <Button variant='outline' className='flex cursor-pointer items-center gap-1' onClick={() => router.push('#')}>
+            Contact Us
+          </Button>
+        </div>
+      </div>
+    </div>
+  )
+}