feat: Implement Supabase authentication, account management UI, and entitlement services.

frontend/app/auth/login/page.tsx

@@ -0,0 +1,21 @@
+import { LoginClient } from "@/components/auth/LoginClient";
+
+type PageProps = {
+  searchParams?: Promise<{ next?: string }>;
+};
+
+function normalizeNextPath(input: string | undefined) {
+  const fallback = "/";
+  const raw = String(input || "").trim();
+  if (!raw) return fallback;
+  if (!raw.startsWith("/")) return fallback;
+  if (raw.startsWith("//")) return fallback;
+  return raw;
+}
+
+export default async function LoginPage({ searchParams }: PageProps) {
+  const params = (await searchParams) || {};
+  const nextPath = normalizeNextPath(params.next);
+  return <LoginClient nextPath={nextPath} />;
+}
+