fix(s3): correct MinIO service port and allow egress

MinIO ClusterIP service listens on port 80 (targetPort 9000).
Config had port 9000 which caused 30s timeout then 502 — gateway
connected to service port 9000 which doesn't exist on the ClusterIP.

Changes:
- configmap.yaml: S3 upstream :9000 → :80
- gateway-config-secret.enc.yaml: same
- network-policy.yaml: add port 80 egress to storage namespace

Verified: S3 adapter now reaches MinIO (403 AccessDenied = auth issue,
not connectivity).

k8s/configmap.yaml

@@ -113,7 +113,7 @@ data:
 
     - serviceName: s3
       upstream:
-        url: http://minio.storage.svc.cluster.local:9000
+        url: http://minio.storage.svc.cluster.local:80
         timeoutSeconds: 30
       auth:
         required: false