feat(openviking): deploy maelstrom-ui Web Studio frontend

- Build/push image: the-seas.local.mk-labs.cloud/library/maelstrom-ui:v0.3.17-1
  (upstream volcengine/openviking web-studio/, pinned to commit 3cd1d4e9)
- Deployment + Service serving the static SPA via nginx (reverse-proxies
  /api, /health, /ready to openviking backend; /bot deliberately NOT proxied)
- Ingress at maelstrom.local.mk-labs.cloud (TLS via letsencrypt-internal)
- ExternalSecret wiring scoped maelstrom-ui-key from
  op://mk-labs/openviking/maelstrom-ui-key into the pod env (MAELSTROM_UI_KEY)

Per approved plan: inbox/ryan/2026-08-14-maelstrom-ui-deployment-plan.md
Key mint + approval: system/inbox/agents/nick-fury/2026-08-14-maelstrom-ui-key-mint-complete.md
Ryan approval: inbox/ryan/2026-08-14-maelstrom-key-approval.md

cluster/platform/openviking/ingress-maelstrom.yaml

@@ -0,0 +1,25 @@
+apiVersion: networking.k8s.io/v1
+kind: Ingress
+metadata:
+  name: maelstrom-ui
+  namespace: openviking
+  annotations:
+    cert-manager.io/cluster-issuer: letsencrypt-prod
+    nginx.ingress.kubernetes.io/ssl-redirect: "true"
+spec:
+  ingressClassName: nginx
+  tls:
+    - hosts:
+        - maelstrom.local.mk-labs.cloud
+      secretName: maelstrom-ui-tls
+  rules:
+    - host: maelstrom.local.mk-labs.cloud
+      http:
+        paths:
+          - path: /
+            pathType: Prefix
+            backend:
+              service:
+                name: maelstrom-ui
+                port:
+                  number: 80