Add ArgoCD GitOps bootstrap contract for railiance01

Define platform-owned AppProjects, root app-of-apps, repository registration
templates, and tenant onboarding docs so issue-core can deploy via ArgoCD.
Ignore encrypted repository secrets locally and cross-link OpenBao delivery
guidance with the new GitOps contract.

argocd/applications/issue-core.application.yaml

@@ -0,0 +1,27 @@
+apiVersion: argoproj.io/v1alpha1
+kind: Application
+metadata:
+  name: issue-core
+  namespace: argocd
+  labels:
+    app.kubernetes.io/part-of: railiance-gitops
+    railiance.io/domain: issue-core
+  annotations:
+    argocd.argoproj.io/sync-wave: "10"
+spec:
+  project: railiance-tenants
+  source:
+    repoURL: https://gitea.coulomb.social/coulomb/issue-core.git
+    targetRevision: main
+    path: k8s/railiance
+  destination:
+    server: https://kubernetes.default.svc
+    namespace: issue-core
+  syncPolicy:
+    automated:
+      prune: true
+      selfHeal: true
+    syncOptions:
+      - CreateNamespace=true
+      - ApplyOutOfSyncOnly=true
+      - PruneLast=true