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

gitops/argocd/application.yaml

@@ -13,20 +13,20 @@ metadata:
 spec:
   project: default
   sources:
-    - repoURL: https://git.luneski.fr/luneski/onelab-k8s.git
+    - repoURL: https://github.com/YOUR_ORG/YOUR_REPO.git
       targetRevision: main
       path: gitops/charts/onelab
       helm:
         releaseName: onelab
         valueFiles:
-          - ../../values/k3s-example.yaml
-    - repoURL: https://git.luneski.fr/luneski/onelab-k8s.git
+          - ../../values/env-example.yaml
+    - repoURL: https://github.com/YOUR_ORG/YOUR_REPO.git
       targetRevision: main
       path: gitops/observability
       helm:
         releaseName: onelab-obs
         valueFiles:
-          - values.yaml
+          - ../../values/observability.yaml
   destination:
     server: https://kubernetes.default.svc
     namespace: onelab