* 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/error.tsx

@@ -0,0 +1,22 @@
+"use client"
+
+import { env } from "@/env/client"
+
+export default function Error({
+  error,
+}: {
+  error: Error & { digest?: string }
+  reset: () => void
+}) {
+  return (
+    <section>
+      <pre>Unable to render header</pre>
+      {env.NEXT_PUBLIC_NODE_ENV === "development" && (
+        <div>
+          <div>{error.message}</div>
+          <pre>{error.stack}</pre>
+        </div>
+      )}
+    </section>
+  )
+}