Function refresh_app_index 

pub async fn refresh_app_index(
    host: &dyn GotifyHost,
    cfg: &GotifyConfig,
) -> bool

Fetch the Gotify /application list and store the name->appid map. Warns (never silently drops) on failure - an unresolved index would otherwise leave every application-name-filtered subscription silently matching nothing while the stream still reports connected. Returns whether the index was stored, so a caller that owes the user an answer about the names can give one.