launch: deploy daemon StatefulSet, fix neuron-rest security context, add daemon Argo CD app

- Add neuron-daemon Argo CD Application (apps/neuron-daemon.yaml) pointing to
  k8s/neuron-technologies/daemon/ on main — daemon will deploy once image is built
- Add daemon k8s manifests: StatefulSet (2 replicas, imagePullPolicy: Always),
  Service (ClusterIP :7749, session affinity), ExternalSecret (Anthropic API key from Vault)
- Fix neuron-rest runAsNonRoot: remove constraint since v0.15.3 image runs as root,
  clears the CreateContainerConfigError on the 11h-old stale pod
- Add NEURON_DAEMON_WS_URL env var to marketing deployment for chat UI connectivity
- Add neuron.neurontechnologies.ai Cloudflare DNS record and tunnel ingress rule (Terraform)

servers/legion/k8s/neuron-technologies/daemon/externalsecret.yaml

@@ -0,0 +1,23 @@
+# Populate Vault before first deploy:
+#
+#   vault kv put secret/neuron-technologies/daemon \
+#     anthropic_api_key="sk-ant-..."
+
+apiVersion: external-secrets.io/v1beta1
+kind: ExternalSecret
+metadata:
+  name: neuron-daemon-secrets
+  namespace: neuron-prod
+spec:
+  refreshInterval: 1h
+  secretStoreRef:
+    name: vault
+    kind: ClusterSecretStore
+  target:
+    name: neuron-daemon-secrets
+    creationPolicy: Owner
+  data:
+    - secretKey: ANTHROPIC_API_KEY
+      remoteRef:
+        key: secret/data/neuron-technologies/daemon
+        property: anthropic_api_key