Function set_felt 

pub(crate) fn set_felt(
    qt: &CxxQtThread<Sioul>,
    shared: &Arc<Shared>,
    uid: &str,
    felt: &str,
) -> String

How a task was, felt (“How was it?”): today’s rating, JSON {cognitive, emotional, anxiety, body, gain} (null: unsaid, never the forecast copied), written alone from the file as it is, whatever the window last read; every value null takes today’s back. Returns what went wrong, else “”.