add_months.sh now targets a single fat node directly: starts a local
Spark cluster via start_spark_cluster.sh, submits jobs, stops the
cluster. No salloc needed.
add_months_multinode.sh is a new script for the multi-node case using
start_spark_and_run.sh from a login node. Usage takes NODES as first arg.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
