fix(setup.sh): set Temporal namespace retention on create (#2675)

## Problem
`helm-prereqs/setup.sh` creates the Temporal namespaces (`cloud`,
`site`, `flow`, `<site-uuid>`) with:
```
temporal operator namespace create -n <ns> --address ... 2>/dev/null || true
```
No `--retention` is passed, and `2>/dev/null || true` swallows any
failure. Depending on the Temporal server's default-retention policy the
create can be rejected/incomplete; the namespace then never exists and
the nico-rest **cloud/site/flow workers CrashLoop** with `Namespace
"<ns>" is not found`. The silent `|| true` makes this invisible during
install.

## Fix
Pass an explicit `--retention 72h` on each namespace create so it
succeeds deterministically regardless of server defaults. (Reproduced on
a clean v0.10.3 install; the same code is still present on `main`.)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Signed-off-by: kirson-git <ekirson@nvidia.com>
Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>
Co-authored-by: Hasan Khan <hasank@nvidia.com>

Author: 3 people

helm-prereqs/setup.sh

@@ -630,12 +630,12 @@ _TEMPORAL_TLS="--tls-cert-path /var/secrets/temporal/certs/server-interservice/t
     --tls-ca-path /var/secrets/temporal/certs/server-interservice/ca.crt \
     --tls-server-name interservice.server.temporal.local"
 kubectl exec -n temporal deploy/temporal-admintools -- \
-    sh -c "temporal operator namespace create -n cloud --address ${_TEMPORAL_ADDR} ${_TEMPORAL_TLS}" 2>/dev/null || true
+    sh -c "temporal operator namespace create -n cloud --retention 72h --address ${_TEMPORAL_ADDR} ${_TEMPORAL_TLS}" 2>/dev/null || true
 kubectl exec -n temporal deploy/temporal-admintools -- \
-    sh -c "temporal operator namespace create -n site --address ${_TEMPORAL_ADDR} ${_TEMPORAL_TLS}" 2>/dev/null || true
+    sh -c "temporal operator namespace create -n site --retention 72h --address ${_TEMPORAL_ADDR} ${_TEMPORAL_TLS}" 2>/dev/null || true
 # flow Temporal namespace — required by NICo Flow workers; pod panics on startup if absent.
 kubectl exec -n temporal deploy/temporal-admintools -- \
-    sh -c "temporal operator namespace create -n flow --address ${_TEMPORAL_ADDR} ${_TEMPORAL_TLS}" 2>/dev/null || true
+    sh -c "temporal operator namespace create -n flow --retention 72h --address ${_TEMPORAL_ADDR} ${_TEMPORAL_TLS}" 2>/dev/null || true
 echo "Temporal namespaces ready"
 
 _SETUP_PHASE="[7g/7] NICo REST helm chart"
@@ -763,7 +763,7 @@ _TEMPORAL_TLS="--tls-cert-path /var/secrets/temporal/certs/server-interservice/t
     --tls-ca-path /var/secrets/temporal/certs/server-interservice/ca.crt \
     --tls-server-name interservice.server.temporal.local"
 kubectl exec -n temporal deploy/temporal-admintools -- \
-    sh -c "temporal operator namespace create -n '${NICO_SITE_UUID}' --address ${_TEMPORAL_ADDR} ${_TEMPORAL_TLS}" 2>/dev/null || true
+    sh -c "temporal operator namespace create -n '${NICO_SITE_UUID}' --retention 72h --address ${_TEMPORAL_ADDR} ${_TEMPORAL_TLS}" 2>/dev/null || true
 echo "Temporal namespace ready"
 
 # FLOW_GRPC_ENABLED toggles the site-agent's Flow gRPC client (see