refactor: serve static frontend with Go APIs

app/billing/page.tsx

@@ -1,10 +1,13 @@
+"use client";
+
 import { BillingManager } from "@/components/billing-manager";
-import { hasSuperAdminAccess } from "@/lib/auth/permissions";
-import { requireAppSession } from "@/lib/server/auth/current-user";
+import { BrowserAuthGuard, useBrowserAuth } from "@/components/browser-auth";
 
-export const dynamic = "force-dynamic";
-
-export default async function BillingPage() {
-  const session = await requireAppSession();
-  return <BillingManager isSuperAdmin={hasSuperAdminAccess(session.user)} />;
+export default function BillingPage() {
+  return <BrowserAuthGuard><BillingContent /></BrowserAuthGuard>;
+}
+
+function BillingContent() {
+  const { isSuperAdmin } = useBrowserAuth();
+  return <BillingManager isSuperAdmin={isSuperAdmin} />;
 }