fix: add -max=0 to volume server for unlimited volumes

- Add -max=0 flag to volume server command
- Allows volume server to create unlimited 50MB volumes
- Fixes 'No writable volumes' error during Spark tests
- Volume server will create new volumes as needed for writes
- Consistent with other integration test configurations

test/java/spark/docker-compose.yml

@@ -27,7 +27,7 @@ services:
     ports:
       - "8080:8080"
       - "18080:18080"
-    command: "volume -mserver=seaweedfs-master:9333 -ip=127.0.0.1 -ip.bind=0.0.0.0 -port=8080 -port.grpc=18080 -publicUrl=127.0.0.1:8080 -preStopSeconds=1"
+    command: "volume -mserver=seaweedfs-master:9333 -ip=127.0.0.1 -ip.bind=0.0.0.0 -port=8080 -port.grpc=18080 -publicUrl=127.0.0.1:8080 -max=0 -preStopSeconds=1"
     depends_on:
       seaweedfs-master:
         condition: service_healthy