feat(nci): add Spark analytics Kubernetes manifests

Wire five Spark jobs (OpeningBook, PlayerStats, PlayerClustering,
PlayerGraph, LiveDashboard) to Kubernetes via native Spark-on-K8s mode.

- spark-analytics/base: ServiceAccount, RBAC Role/RoleBinding (driver
  executor pod management), two PVCs (10Gi output, 2Gi checkpoint),
  four CronJobs for batch analytics, one Deployment for the Structured
  Streaming live dashboard
- spark-analytics/eu-central-1-prod: namespace overlay pinning image
  to 0.1.0 with strategic merge patches that update both the container
  image field and the spark.kubernetes.container.image conf arg
- eu-central-1/argo-apps/spark-analytics: ArgoCD Application pointing
  at the prod overlay with automated prune+selfHeal sync

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

eu-central-1/argo-apps/spark-analytics/spark-analytics.yaml

@@ -0,0 +1,18 @@
+apiVersion: argoproj.io/v1alpha1
+kind: Application
+metadata:
+  name: spark-analytics
+  namespace: argocd
+spec:
+  project: default
+  destination:
+    namespace: nowchess
+    server: https://kubernetes.default.svc
+  sources:
+    - repoURL: git@git.janis-eccarius.de:NowChess/Gitops.git
+      path: ./spark-analytics/eu-central-1-prod
+      targetRevision: main
+  syncPolicy:
+    automated:
+      prune: true
+      selfHeal: true