Appends a tag JSONL entry. Pass NULL to clear the tag.
list_sessions() reads the LAST tag — most recent wins.
Tags are Unicode-sanitized before storing.
Examples
# \donttest{
sessions <- list_sessions(limit = 1L)
if (length(sessions) > 0) {
tag_session(sessions[[1]]$session_id, "important")
# Clear the tag
tag_session(sessions[[1]]$session_id, NULL)
}
# }