Function apply_oneshot_types 

pub fn apply_oneshot_types(
    stats: &mut SystemdUnitStats,
    oneshot_types: &HashMap<String, bool>,
    config: &UnitsConfig,
)

Recompute unhealthy for tracked units given resolved service types.

Units missing from oneshot_types (lookup failed or never a candidate) are treated as “not oneshot”, matching the D-Bus path’s assumption.