lisk mainnet: add op-reth datadir snapshot restore script for bench seeding

op/lisk/mainnet/scripts/download-apply-snapshot.sh

@@ -0,0 +1,44 @@
+#!/bin/sh
+set -eu
+
+# Bench-seed helper for Lisk op-reth: fetch a datadir snapshot into RETH_DATA_DIR once.
+# Idempotent — skips when chain data is already present.
+
+RETH_DATA_DIR="${RETH_DATA_DIR:-/root/.local/share/reth}"
+SNAPSHOT_URL="${SNAPSHOT_URL:-}"
+
+if [ -d "${RETH_DATA_DIR}/db" ] && [ -n "$(ls -A "${RETH_DATA_DIR}/db" 2>/dev/null || true)" ]; then
+  echo "snapshot-restore: ${RETH_DATA_DIR}/db already populated; skipping"
+  exit 0
+fi
+
+if [ -z "${SNAPSHOT_URL}" ]; then
+  echo "snapshot-restore: SNAPSHOT_URL is unset; skipping" >&2
+  exit 1
+fi
+
+SNAPSHOT_DIR="${SNAPSHOT_DIR:-/tmp/lisk-snapshot}"
+SNAPSHOT_FILE="${SNAPSHOT_DIR}/$(basename "${SNAPSHOT_URL}")"
+
+mkdir -p "${RETH_DATA_DIR}" "${SNAPSHOT_DIR}"
+
+echo "snapshot-restore: downloading ${SNAPSHOT_URL}"
+curl -fsSL --retry 3 --retry-delay 10 -o "${SNAPSHOT_FILE}" "${SNAPSHOT_URL}"
+
+case "${SNAPSHOT_FILE}" in
+  *.tar.lz4)
+    echo "snapshot-restore: extracting lz4 datadir snapshot into ${RETH_DATA_DIR}"
+    tar --directory "${RETH_DATA_DIR}" -I lz4 -xf "${SNAPSHOT_FILE}"
+    ;;
+  *.tar.gz|*.tgz|*.tar)
+    echo "snapshot-restore: extracting datadir snapshot into ${RETH_DATA_DIR}"
+    tar --directory "${RETH_DATA_DIR}" -xf "${SNAPSHOT_FILE}"
+    ;;
+  *)
+    echo "snapshot-restore: unsupported snapshot format: ${SNAPSHOT_FILE}" >&2
+    exit 1
+    ;;
+esac
+
+rm -rf "${SNAPSHOT_DIR}"
+echo "snapshot-restore: done"