Add initial Portal version

src/lib/session.ts

@@ -0,0 +1,19 @@
+import { auth } from "@/lib/auth";
+import type { SessionUser } from "@/types";
+
+export async function getSessionUser(): Promise<SessionUser | null> {
+  const session = await auth();
+  return (session as any)?.platformUser ?? null;
+}
+
+export async function requireSession(): Promise<SessionUser> {
+  const user = await getSessionUser();
+  if (!user) throw new Error("Unauthorized");
+  return user;
+}
+
+export async function requirePlatformRole(): Promise<SessionUser> {
+  const user = await requireSession();
+  if (!user.isPlatform) throw new Error("Forbidden: platform role required");
+  return user;
+}