feat(03-01): protect /portal routes and update post-login redirect

- middleware.ts: add /portal/:path* to matcher array
- auth.config.ts: add isPortalRoute check, redirect unauthenticated to /agent/login
- auth.config.ts: change post-login redirect from /agent/dashboard to /portal/dashboard
- agent dashboard page: replace stub with redirect to /portal/dashboard

teressa-copeland-homes/middleware.ts

@@ -5,5 +5,5 @@ const { auth } = NextAuth(authConfig);
 export default auth;
 
 export const config = {
-  matcher: ["/agent/:path*"],
+  matcher: ["/agent/:path*", "/portal/:path*"],
 };