* move setLang() to a root layout

* fix: findLang only returns acceptable languages
* fix: fallback to use header x-lang if we haven't setLang yet
* fix: languageSchema, allow uppercase

Approved-by: Linus Flood

app/[lang]/(live)/@header/page.tsx

@@ -0,0 +1,21 @@
+import { Suspense } from "react"
+
+import { env } from "@/env/server"
+
+import CurrentHeader from "@/components/Current/Header"
+import HeaderFallback from "@/components/Current/Header/HeaderFallback"
+import Header from "@/components/Header"
+
+import type { LangParams, PageArgs } from "@/types/params"
+
+export default function HeaderPage({}: PageArgs<LangParams>) {
+  if (env.HIDE_FOR_NEXT_RELEASE) {
+    return (
+      <Suspense fallback={<HeaderFallback />}>
+        <CurrentHeader />
+      </Suspense>
+    )
+  }
+
+  return <Header />
+}