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/jsonpatch-multisource.json

@@ -2,21 +2,21 @@
   {"op": "remove", "path": "/spec/source"},
   {"op": "add", "path": "/spec/sources", "value": [
     {
-      "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"]
+        "valueFiles": ["../../values/env-example.yaml"]
       }
     },
     {
-      "repoURL": "https://git.luneski.fr/luneski/onelab-k8s.git",
+      "repoURL": "https://github.com/YOUR_ORG/YOUR_REPO.git",
       "targetRevision": "main",
       "path": "gitops/observability",
       "helm": {
         "releaseName": "onelab-obs",
-        "valueFiles": ["values.yaml"]
+        "valueFiles": ["../../values/observability.yaml"]
       }
     }
   ]}