docs: note soteria bring-up dependencies

README.md

@@ -14,6 +14,22 @@ Policies are stored in a Kubernetes secret and evaluated on a timer. Metrics are
 
 The following are notes for future Brad.
 
+## Bring-up dependencies
+
+Soteria is not how Atlas gets storage back. It is useful after Kubernetes and Longhorn are already alive enough to answer API calls.
+
+It needs:
+
+- Kubernetes API, service DNS, and Soteria's service account/RBAC
+- Longhorn managers/backend service reachable at `SOTERIA_LONGHORN_URL`
+- Longhorn backup target already configured and reachable if backups/restores are expected to work
+- the `soteria` namespace and the Kubernetes secret used for backup policies
+- ingress/proxy/auth headers if the UI is exposed with auth enabled
+- B2 credentials and bucket access only if B2 usage reporting is enabled
+- Prometheus/Grafana only for visibility; the service can run without dashboards
+
+In a total bring-up, fix nodes, disks, Longhorn, and Flux first. Start using Soteria once PVC inventory is visible and Longhorn can make backups without being nursed.
+
 Main endpoints:
 
 - `GET /healthz`, `GET /readyz`, `GET /metrics`