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>

eslint.config.mjs

@@ -0,0 +1,25 @@
+import { dirname } from "path";
+import { fileURLToPath } from "url";
+import { FlatCompat } from "@eslint/eslintrc";
+
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = dirname(__filename);
+
+const compat = new FlatCompat({
+  baseDirectory: __dirname,
+});
+
+const eslintConfig = [
+  ...compat.extends("next/core-web-vitals", "next/typescript"),
+  {
+    ignores: [
+      "node_modules/**",
+      ".next/**",
+      "out/**",
+      "build/**",
+      "next-env.d.ts",
+    ],
+  },
+];
+
+export default eslintConfig;