fornax: fix crash-looping coordinator, add UI deployment

- Fix liveness/readiness probe paths from /api/v2/app/version (qBittorrent)
  to /health and /health/ready (Fornax Express server). Pod was restarting
  every ~30s due to probe failures against wrong endpoint.
- Add fornax-ui deployment and service for React dashboard
  (image: fornax/ui:latest, nginx on port 80)
- Split ingress: /api and /health → coordinator:3000, / → ui:80
- Update kustomization to include UI resources

servers/legion/k8s/fornax/ui/service.yaml

@@ -0,0 +1,15 @@
+apiVersion: v1
+kind: Service
+metadata:
+  name: fornax-ui
+  namespace: media
+  labels:
+    app: fornax-ui
+spec:
+  selector:
+    app: fornax-ui
+  ports:
+    - name: http
+      port: 80
+      targetPort: 80
+  type: ClusterIP