feat: add signin link to the signup page

apps/landing/src/app/(auth)/signup/page.tsx

@@ -1,5 +1,6 @@
 import { LogoSimple } from '@/app/_components/logo';
 import { Metadata } from 'next';
+import Link from 'next/link';
 import { SignupForm } from './_components/signup-form';
 
 export const metadata: Metadata = {
@@ -18,6 +19,18 @@ export default function Page() {
       </div>
 
       <SignupForm />
+
+      <div className="w-full space-y-4">
+        <p className="text-muted-foreground px-4 text-center text-xs leading-5 text-balance sm:text-sm">
+          Sudah punya akun?{' '}
+          <Link
+            href="/signin"
+            className="font-bold hover:underline hover:underline-offset-4 transition-colors text-primary-500"
+          >
+            Masuk
+          </Link>
+        </p>
+      </div>
     </>
   );
 }