feat(spark): replace Bitnami chart with Apache Spark manifests

Bitnami Spark chart requires a Broadcom commercial license. Replace with
plain Deployments using apache/spark:3.5.4-scala2.13-java17-ubuntu
(Apache 2.0, same image used by the analytics jobs):
- spark-master: Deployment + ClusterIP Service (ports 7077/8080)
- spark-worker: Deployment, 2 replicas, connects to spark-master:7077
- spark-history-server: updated to apache/spark image
Ingress backend corrected to spark-master:8080.

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

spark-cluster/base/ingress.yaml

@@ -15,9 +15,9 @@ spec:
             pathType: Prefix
             backend:
               service:
-                name: spark-master-svc
+                name: spark-master
                 port:
-                  number: 80
+                  number: 8080
 ---
 apiVersion: networking.k8s.io/v1
 kind: Ingress
@@ -26,11 +26,6 @@ metadata:
   labels:
     app.kubernetes.io/name: spark-cluster
     app.kubernetes.io/part-of: nowchess
-  annotations:
-    # NOTE: The Bitnami spark chart 9.2.10 does not include a standalone history
-    # server deployment or service. This Ingress is a placeholder. To activate
-    # history server access, deploy a separate spark-history-server Deployment
-    # and Service named spark-history-server-svc on port 18080.
 spec:
   ingressClassName: traefik
   rules: