Fix ClickHouse OOM during Proxmox nightly backups

Increase ClickHouse memory limit from 1Gi to 2Gi and reduce default
batch size from 5000 to 500. During VM backup snapshots, I/O contention
prevents ClickHouse from flushing writes fast enough, causing buffer
accumulation that exceeds the 1Gi container limit.

Co-Authored-By: Claude Opus 4.6 <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 = 5_000;
+    private int batchSize = 500;
     private long flushIntervalMs = 1_000;
 
     public int getBufferCapacity() {

deploy/clickhouse.yaml

@@ -37,7 +37,7 @@ spec:
               memory: "512Mi"
               cpu: "200m"
             limits:
-              memory: "1Gi"
+              memory: "2Gi"
               cpu: "1000m"
   volumeClaimTemplates:
     - metadata: