Add authenticated login and SSO protection

app/api/auth/me/route.ts

@@ -0,0 +1,16 @@
+import { getAuthRuntimeConfig } from "@/lib/auth/config";
+import { jsonOk } from "@/lib/server/api";
+import { getOptionalAuthSession } from "@/lib/server/auth/current-user";
+
+export const runtime = "nodejs";
+
+export async function GET() {
+  const config = getAuthRuntimeConfig();
+  const session = await getOptionalAuthSession();
+  return jsonOk({
+    authenticated: Boolean(session),
+    authRequired: config.required,
+    authConfigured: config.configured,
+    user: session?.user || null
+  });
+}