feat: add notes

src/content/docs/applications/harbor.mdx

@@ -13,3 +13,13 @@ hero:
       link: https://gitea.alexlebens.dev/alexlebens/infrastructure/src/branch/main/clusters/cl01tl/helm/harbor
       icon: right-arrow
 ---
+
+# Purpose
+
+Pull through cache and registry for personal images built in Gitea.
+
+# Notes
+
+Talos is configured to direct pulls to Docker, Github, and others to Harbor first. Stores these images as a cache to avoid rate limiting, primarily by Docker hub.
+
+Any of my own images also get stored here to deploy.