feat: add notes

src/content/docs/applications/authentik.mdx

@@ -13,3 +13,17 @@ hero:
       link: https://gitea.alexlebens.dev/alexlebens/infrastructure/src/branch/main/clusters/cl01tl/helm/authentik
       icon: right-arrow
 ---
+
+import { Aside } from '@astrojs/starlight/components';
+
+<Aside>This app has public facing endpoint, at [auth.alexlebens.dev](https://auth.alexlebens.dev)</Aside>
+
+<Aside type="tip">Has an internal [Grafana Dashboard](https://grafana.alexlebens.net/goto/efiq29z9u4dmob?orgId=1)</Aside>
+
+# Purpose
+
+Single sign on authentication for applications that support OIDC.
+
+# Notes
+
+Available at public, local, and Tailscale endpoints. Apps are configured for their like endppoints.