feat(web): complete MVP0 public layout, banner, and SEO baseline

apps/web/src/components/public-site-header.tsx

@@ -0,0 +1,44 @@
+"use client"
+
+import { useTranslations } from "next-intl"
+
+import { Link } from "@/i18n/navigation"
+
+import { LanguageSwitcher } from "./language-switcher"
+
+export function PublicSiteHeader() {
+  const t = useTranslations("Layout")
+
+  const navItems = [
+    { href: "/", label: t("nav.home") },
+    { href: "/about", label: t("nav.about") },
+    { href: "/contact", label: t("nav.contact") },
+  ]
+
+  return (
+    <header className="border-b border-neutral-200 bg-white/80 backdrop-blur">
+      <div className="mx-auto flex w-full max-w-6xl flex-wrap items-center justify-between gap-4 px-6 py-4">
+        <Link
+          href="/"
+          className="text-sm font-semibold uppercase tracking-[0.2em] text-neutral-700"
+        >
+          {t("brand")}
+        </Link>
+
+        <nav className="flex flex-wrap items-center gap-2">
+          {navItems.map((item) => (
+            <Link
+              key={item.href}
+              href={item.href}
+              className="rounded-md border border-neutral-300 px-3 py-1.5 text-sm font-medium text-neutral-700 hover:bg-neutral-100"
+            >
+              {item.label}
+            </Link>
+          ))}
+        </nav>
+
+        <LanguageSwitcher />
+      </div>
+    </header>
+  )
+}