dump_db.sh no longer lives under $TARGET, so its own default dump
directory (relative to wherever the script is) would land outside the
backed-up tree. Pin DUMP_SCRIPT to /opt/backup-agent/dump_db.sh and
export DUMP_DIR explicitly so dumps still land in $TARGET/mariadb/dump
regardless of where the script itself is deployed.
Also drop the healthcheck integration (HEALTHCHECK_URL, send_healthcheck,
curl requirement) from borg-backup.sh per request - no monitoring hook
wanted for now.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>