Establish Railiance Fabric graph model

fabric/bindings/flex-auth-runtime-secrets-openbao.yaml

@@ -0,0 +1,16 @@
+apiVersion: railiance.fabric/v1alpha1
+kind: BindingAssertion
+metadata:
+  id: flex-auth.api.runtime-secrets-to-openbao
+  name: flex-auth runtime secrets binding
+  owner: flex-auth
+  repo: flex-auth
+  domain: railiance
+spec:
+  lifecycle: active
+  environments: [dev, staging, prod]
+  dependency_id: flex-auth.api.needs-runtime-secrets
+  provider_capability_id: railiance-platform.openbao.runtime-secrets
+  provider_interface_id: railiance-platform.openbao.kv-v2
+  status: exact
+  rationale: flex-auth uses OpenBao KV v2 as the runtime secrets provider.