Build Kozmos QR menu site — full implementation

Next.js 16 App Router, TR/EN i18n via [lang] routing and proxy.ts,
Tailwind v4, minimal list menu style, sticky bottom tab bar with
Intersection Observer, PWA manifest, WhatsApp fixed button.

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

app/[lang]/layout.tsx

@@ -0,0 +1,42 @@
+import type { Metadata } from 'next'
+import { notFound } from 'next/navigation'
+import { getDictionary, hasLocale } from './dictionaries'
+
+export async function generateStaticParams() {
+  return [{ lang: 'tr' }, { lang: 'en' }]
+}
+
+export async function generateMetadata({
+  params,
+}: {
+  params: Promise<{ lang: string }>
+}): Promise<Metadata> {
+  const { lang } = await params
+  if (!hasLocale(lang)) return {}
+  const dict = await getDictionary(lang)
+  return {
+    title: dict.meta.title,
+    description: dict.meta.description,
+    manifest: '/manifest.webmanifest',
+    appleWebApp: {
+      capable: true,
+      statusBarStyle: 'black-translucent',
+      title: 'Kozmos',
+    },
+    other: {
+      'theme-color': '#3D2B1F',
+    },
+  }
+}
+
+export default async function LangLayout({
+  children,
+  params,
+}: {
+  children: React.ReactNode
+  params: Promise<{ lang: string }>
+}) {
+  const { lang } = await params
+  if (!hasLocale(lang)) notFound()
+  return <>{children}</>
+}