Fix ClickHouse OOM on batch insert: reduce batch size, increase memory

Execution rows are wide (29 cols with serialized arrays/JSON), so 500
rows can exceed ClickHouse's memory limit. Reduce default batch size
from 500 to 100 and bump ClickHouse memory limit from 2Gi to 4Gi.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

deploy/clickhouse.yaml

@@ -40,10 +40,10 @@ spec:
               mountPath: /var/lib/clickhouse
           resources:
             requests:
-              memory: "512Mi"
+              memory: "1Gi"
               cpu: "200m"
             limits:
-              memory: "2Gi"
+              memory: "4Gi"
               cpu: "1000m"
           livenessProbe:
             httpGet: