fix(k8s,docs): scale ddb-cluster to single instance, pin minio to storage namespace, document 3-CP topology in USAGE

k8s/infrastructure/minio/buckets.yaml

@@ -4,7 +4,7 @@ apiVersion: minio.min.io/v1alpha1
 kind: Bucket
 metadata:
   name: riotpiao-models
-  namespace: minio
+  namespace: storage
 spec:
   name: riotpiao-models
   versioning:
@@ -20,7 +20,7 @@ apiVersion: minio.min.io/v1alpha1
 kind: Policy
 metadata:
   name: policy-ollama
-  namespace: minio
+  namespace: storage
 spec:
   name: policy-ollama
   statements:
@@ -42,7 +42,7 @@ apiVersion: minio.min.io/v1alpha1
 kind: User
 metadata:
   name: user-ollama
-  namespace: minio
+  namespace: storage
 spec:
   accessKey: ollama-access-key
   secretKey: ollama-secret-key-changeme  # Override via Secret