gitops: public-safe values, docs; remove legacy app/resources

- Sanitize placeholders, centralize values under gitops/values/
- Argo Application placeholder repoURL; env-example + observability.yaml
- Remove Swarm app/, resources/, install.sh; add root README

Made-with: Cursor

README.md

@@ -0,0 +1,11 @@
+# OneLab (Kubernetes)
+
+Deploy OneLab with **Argo CD** and Helm using the manifests under [`gitops/`](gitops/).
+
+**Documentation:** [gitops/README.md](gitops/README.md) — prerequisites, configuration, bootstrap, and troubleshooting.
+
+```bash
+kubectl apply -f gitops/argocd/application.yaml
+```
+
+Edit `gitops/argocd/application.yaml` (`repoURL`, `targetRevision`) and `gitops/values/*.yaml` before syncing in production.