keyboard radiogroup, modal focus trap, nav session hydration

src/components/layout/nav-shell.tsx

@@ -6,6 +6,7 @@ import { signOut, useSession } from "next-auth/react";
 import { usePathname } from "@/i18n/navigation";
 import { Link } from "@/i18n/navigation";
 import { SessionProvider } from "next-auth/react";
+import type { Session } from "next-auth";
 import { LanguageSwitcher } from "@/components/ui/language-switcher";
 
 function NavBar() {
@@ -211,9 +212,19 @@ function NavLink({
   );
 }
 
-export function NavShell({ children }: { children: React.ReactNode }) {
+export function NavShell({
+  children,
+  session,
+}: {
+  children: React.ReactNode;
+  // Server-resolved session passed down from the locale layout. Seeding
+  // SessionProvider with it means useSession() is populated on the first
+  // client render, so the nav links render immediately instead of
+  // popping in after the client-side session fetch (CLS / flash).
+  session: Session | null;
+}) {
   return (
-    <SessionProvider>
+    <SessionProvider session={session}>
       <NavBar />
       <main className="mx-auto max-w-6xl px-5 py-8">{children}</main>
     </SessionProvider>