fix(neuron-prod): set neuron-marketing-hpa minReplicas to 1

Kubernetes rejects minReplicas=0 unless at least one Object or
External metric is configured. With only a Resource (CPU) metric,
the HPA is invalid:

  HorizontalPodAutoscaler.autoscaling "neuron-marketing-hpa"
  is invalid: [spec.minReplicas: Invalid value: 0: must be greater
  than or equal to 1, spec.metrics: Forbidden: must specify at
  least one Object or External metric to support scaling to zero
  replicas]

This was blocking the entire neuron-prod Argo CD sync — every
manifest in the directory had to be applied individually after
this single resource caused the multi-resource patch to fail.
The dharma NetworkPolicy applied today only because Argo retried
individually after the failure.

The file header already states "minReplicas=1 prevents unnecessary
idle waste" as the intent for this single-Legion-node period;
this brings the marketing HPA into line with the other two.

servers/legion/k8s/neuron-technologies/prod/hpa.yaml

@@ -82,7 +82,12 @@ spec:
     apiVersion: apps/v1
     kind: Deployment
     name: neuron-marketing
-  minReplicas: 0
+  # minReplicas=1 to match the file's own convention (see header comment).
+  # Kubernetes only allows minReplicas=0 when at least one Object or External
+  # metric is configured (queue depth, custom signal, etc.); with only a
+  # Resource (CPU) metric, scale-to-zero is rejected and the whole HPA is
+  # invalid — which was blocking neuron-prod's Argo CD sync.
+  minReplicas: 1
   maxReplicas: 8
   metrics:
     - type: Resource

servers/legion/k8s/neuron-technologies/prod/network-policy.yaml

@@ -117,6 +117,32 @@ spec:
             matchLabels:
               kubernetes.io/metadata.name: neuron-prod
 ---
+# ── dharma: accept from Traefik (kube-system) and neuron-prod namespace ──────
+# The dharma pod was healthy and the IngressRoute was correct, but cross-
+# namespace ingress from kube-system (Traefik) was denied by default-deny-all,
+# so every external request landed at Traefik and bounced back as 502. This
+# allow rule mirrors `allow-mcp-ingress` and brings dharma into line with the
+# other neuron-prod services.
+apiVersion: networking.k8s.io/v1
+kind: NetworkPolicy
+metadata:
+  name: allow-dharma-ingress
+  namespace: neuron-prod
+spec:
+  podSelector:
+    matchLabels:
+      app: dharma
+  policyTypes:
+    - Ingress
+  ingress:
+    - from:
+        - namespaceSelector:
+            matchLabels:
+              kubernetes.io/metadata.name: kube-system
+        - namespaceSelector:
+            matchLabels:
+              kubernetes.io/metadata.name: neuron-prod
+---
 # ── Egress: all prod pods may reach platform (postgres/redis), vault,
 #            monitoring (alloy OTLP), kube-dns, and the internet (external APIs) ─
 apiVersion: networking.k8s.io/v1