feat: initialize Next.js v15 starter kit with Korean support

Set up Next.js v15 starter kit with App Router architecture including:
- TailwindCSS v4 with CSS-based config and OKLCH color system
- shadcn/ui components (New York style) with Lucide icons
- next-themes for light/dark/system theme toggle (Korean labels)
- Layout components: navbar, footer, theme-toggle
- Import aliases and TypeScript configuration

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

components/layout/footer.tsx

@@ -0,0 +1,35 @@
+import Link from "next/link"
+
+export function Footer() {
+  return (
+    <footer className="border-t border-border/40">
+      <div className="container mx-auto flex flex-col items-center justify-between gap-4 py-10 md:h-24 md:flex-row md:py-0 px-4">
+        <div className="flex flex-col items-center gap-4 px-8 md:flex-row md:gap-2 md:px-0">
+          <p className="text-center text-sm leading-loose text-muted-foreground md:text-left">
+            <Link
+              href="/"
+              className="font-medium underline underline-offset-4"
+            >
+              Next.js Starter Kit
+            </Link>
+            로 구축되었습니다. 소스 코드는{" "}
+            <Link
+              href="#"
+              target="_blank"
+              rel="noreferrer"
+              className="font-medium underline underline-offset-4"
+            >
+              GitHub
+            </Link>
+            에서 확인할 수 있습니다.
+          </p>
+        </div>
+        <div className="flex items-center space-x-1">
+          <p className="text-sm text-muted-foreground">
+            © 2025 All rights reserved.
+          </p>
+        </div>
+      </div>
+    </footer>
+  )
+}