feat(offsite): 异地副本加入 registry 用户镜像，按摘要加密去重，索引按版本保留 14 天，新增 fetch-images 回推恢复

deploy/bootstrap.sh

@@ -3166,7 +3166,7 @@ install_offsite_timer() {
   fi
   cat > "$OFFSITE_SERVICE" <<EOF
 [Unit]
-Description=Felis off-site copy (world archives and database bundles, encrypted, to the [offsite] bucket)
+Description=Felis off-site copy (world archives, database bundles and user registry images, encrypted, to the [offsite] bucket)
 After=network-online.target k3s.service postgresql.service felis-db-backup.service
 Wants=network-online.target