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>

components/Header.tsx

@@ -0,0 +1,45 @@
+import Link from 'next/link'
+
+type Dict = {
+  header: { tagline: string }
+  langSwitch: { current: string; other: string; otherHref: string }
+}
+
+export default function Header({ dict }: { dict: Dict }) {
+  return (
+    <header
+      className="fixed top-0 left-0 right-0 z-40 bg-coffee"
+      style={{ height: 'var(--header-h)' }}
+    >
+      {/* Thin teal accent line at bottom */}
+      <div className="absolute bottom-0 left-0 right-0 h-px bg-teal opacity-40" />
+
+      <div className="flex items-center justify-between h-full px-5">
+        {/* Logo */}
+        <div className="flex flex-col leading-none">
+          <span className="font-display text-cream text-xl font-semibold tracking-[0.18em] uppercase">
+            KOZMOS
+          </span>
+          <span className="font-body text-teal text-[0.6rem] font-medium tracking-[0.22em] uppercase mt-0.5">
+            {dict.header.tagline}
+          </span>
+        </div>
+
+        {/* Language switcher */}
+        <Link
+          href={dict.langSwitch.otherHref}
+          className="flex items-center gap-1.5 group"
+          aria-label={`Switch to ${dict.langSwitch.other}`}
+        >
+          <span className="font-body text-xs font-semibold text-cream/40 tracking-wider">
+            {dict.langSwitch.current}
+          </span>
+          <span className="font-body text-xs text-cream/20">·</span>
+          <span className="font-body text-xs font-semibold text-teal tracking-wider group-hover:text-cream transition-colors duration-200">
+            {dict.langSwitch.other}
+          </span>
+        </Link>
+      </div>
+    </header>
+  )
+}