Add Next.js 15 app skeleton with Tailwind v4 and shadcn/ui

Next.js 15 + React 19, Tailwind v4, shadcn/ui (button, card, input,
dialog), postcss config, standalone output. ESLint extended with
next/core-web-vitals via eslint-config-next flat export. node-linker=hoisted
in .npmrc to allow standalone builds on Windows (symlink restriction).
next-env.d.ts added to .gitignore.

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

src/app/page.tsx

@@ -0,0 +1,8 @@
+export default function Page() {
+  return (
+    <main className="flex min-h-screen flex-col items-center justify-center p-8">
+      <h1 className="text-4xl font-bold">famapp</h1>
+      <p className="mt-4 text-muted-foreground">Dashboard coming soon</p>
+    </main>
+  );
+}