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>

cameleer3-server-app/src/main/java/com/cameleer3/server/app/config/IngestionConfig.java

@@ -12,7 +12,7 @@ import org.springframework.boot.context.properties.ConfigurationProperties;
 public class IngestionConfig {
 
     private int bufferCapacity = 50_000;
-    private int batchSize = 500;
+    private int batchSize = 100;
     private long flushIntervalMs = 1_000;
 
     public int getBufferCapacity() {